AITAH for not caring my best friend ran away crying after giving her the silent treatment?

Ive never done this before so excuse any of the typos or misunderstandings ill try to answer everyones questions and comments if needed. ill be using fake names (from mean girls) just in case lmao :)

My best friend (regina) and i have only been friends for almost a year and everything has been fine until this. We are gym partners and tend to go as many times a week that we can since we both have been wanting to better our health and bodies and we felt unmotivated so we agreed it would be nice to have each other to go with

2 days ago I went with regina and her brother (her brother is also our close friend and this was his first time going with us) to the gym. We arrived and i immediately felt gross, like physically slight nausea. We started our routine like usual and by the end of it i was exhausted i felt worse than before. Regina could always handle more weight than me on the machines. She made sure to let her brother know by saying "well i ALWAYS have to do more than *my name* can" i always compliment her and encourage her but i've never felt the same in return. on our last machine of the day i had awful shape and felt forced to do it because regina was doing it. and Honestly i'm scared of not progressing. She began to laugh at me and said "omg what is that form" i was shaking sweating and on the verge of passing out i got up and said that i was about to cry and that obviously i cant do as much as she can, and how its sucks because it makes me feel shitty. i then and ran outside, it was 8pm and i sat outside in the cold crying my eyes out. She's always made comments like that and i have pretty tough skin but today was just not the day. i was so tired of having to feel like i was competing with my own friend and i felt like she was using/insulting my abilities to feel better about herself. And i'll admit i am jealous she can do better than me but i will always encourage her and tell her she's doing amazing despite of it because i love her and i'm happy for her. But Whenever i think i'm seeing process she always says "you look the same it's impossible to see progress its only been a couple of weeks". Regina and her brother both didn't seem to care i left because they finished there workout as i waited 20 minutes. they came outside laughing talking about how "you missed the cooldown" i was crying and obviously very hurt. Her brother was nice and tried to comfort me. Regina then asked why i was crying and I replied with something along the lines of "idk if i'm being sensitive right now, but i'm crying because of you, you made me cry, you laughed at me when i was trying" she then said an inside joke which basically agreed that i was being sensitive and that it wasn't a big deal and laughed and that completely pissed me off and further hurt me After this they decided to go eat, I ignored her the whole time and was pretty silent only saying small things when replying to her brother.

the next day at school (i'm a senior in high school) regina came up to my friend (karen) and i. i completely ignored her (she never said anything to me but it was obvious i didn't want to talk to her as i didn't even acknowledge she was there) Mid conversation with Karen she ran off crying. I didn't move a muscle and stayed where i was, Karen instantly started asking questions saying how "she's crying" and "she thinks you're mad at her." I very harshly responded with "its because i am mad, yesterday when i ran out crying she didn't seem to care so its simply not my problem" petty i know, but i was just hurt it sucks when its such a sensitive subject to since i've suffered with an eating disorder and i just wanted my friend to be supportive. she doesn't owe me anything but it would be nice to receive that support from a friend and as a gym partner i was expecting it because imo thats the whole point of having each other.

During lunch Karen was pushing me to talk to her but i refused, i just wasn't ready she grabbed my hand and pulled me towards her and it made me completely uncomfortable. I told myself id be able to talk to her about it on my own accord and when I felt ready and right now was not the time. I expressed to karen telling her "this isn't funny you're making me uncomfortable let go of my hand" she started complaining and saying "I just want you both to make up you're both so stubborn" and "I just don't wanna be in the middle of this" at that time she also told me regina was being just as stubborn and said "it's not my problem" which made me even angrier because it is, its because of regina's actions this situation is even occurring. But anyways i was quick to reassure Karen she wasn't in the middle and decided to no longer confide in her over the matter to make sure she didn't feel that way. But at the same time it made me upset she acted that way since i felt like she didn't have the right to decide when i'm comfortable to talk to her. While thinking of everything that had just happened i was filled in anger and I left.

I went to sit with some other friends. Regina texted me "lets just talk about this, what did i do" i sent her a message explaining what she did and she said she "I don't want to have this discussion through text, just come talk to me in person you're here right now" and made it clear she just wanted to get this over with because, "we are both forced". i simply told her i didn't feel like talking to her yet because i was still hurt and not in the right state. Although i was confused about how she didn't know bc i had told her that day at the gym what made me upset. she said that was okay, and apologized expressing how it was just a joke and she never thought it would hurt my feelings. she said she genuinely didn't mean to act like that, she gets awkward around people crying and she was just trying to make me laugh. And how she doesn't recall acting that way, to just let her know when i'm ready to talk. I appreciated that and felt a little better but just still space and assumed she wasn't mad at me.

Now cutting forward to today we have all of our classes together and we sit together in all of them. I went to school with the mindset of talking to her and telling her I understand just to be more considerate, even if they are jokes. I was expecting everything to be okay. In the first class we had together she didn't even look at me and ignored i was even there. i tried to talk to her since our teacher asked to talk with our partners, and she completely ignored me. Instead of answering my "so what did you think?" she pointed at her computer screen with an annoyed/serious expression, where the answer to the teachers question was. she then rolled her eyes and went back to texting. that infuriated me, i tired to talk to her and i don't feel like she has a reason to be upset because she was the one to make fun of me.

When i walked in late to my spanish class she had another one of her friends in my seat, regina seemed to not care, so i went to sit with another friend (Damian) Which i really appreciate because he's been there for me and has been amazing about joining his friend group for lunch and the rest of my classes.

Today i also found out that she used to bully people in middle school and how she isn't a great person. which completely shocked me because she's never acted like that with me. But people change. im surprised because i've always mentioned my past and very personal things and she's never mentioned anything about that. I mean, I always knew that some of the things she says are not the best but i always assumed it came out of a place of hurt. I made me further rethink our friendship.

I never expected her to react like this since i'm used to just getting over things with my friends bc they try to talk to me. I wanted her to reach out but not in the way that she did. It seemed completely forced and she even admitted it herself. I will admit i was being petty but i just want to feel like she's genuinely sorry and so far i just don't feel that way.

So reddit AITAH and if so how can i make this better? i don't wanna lose our friendship but after seeing her attitude about all of this and also just not wanting to talk to me, i don't know what to do. Did i do something wrong i'm just not seeing?