Above average intelligence, but b- student.

This has been bugging me about myself recently. How does that work? I really don't get it. I have really bad add, but I feel like being 120+ iq should compensate for that. And yet in high school I barely cracked 75% in most subjects.

To my credit, hardly being able to focus and study and scoring above C is probably an achievement. I just wish I could do better and reach my full potential.