Has anyone else felt like they're being watched, but there's no one there?

I know this sounds crazy, but I swear something is watching me. I don’t mean online—like, physically watching me. At first, I thought I was just paranoid, but I keep seeing movement in the corner of my eye. I’ll turn, and nothing is there. I thought maybe it was just stress, but now things are changing. Little things in my apartment are moved. My dog growls at nothing. My phone screen sometimes lights up like someone’s touching it.

I don’t know. Maybe I’m losing it. Has anyone else ever had something like this happen?