I work with a lot of people (both adults and students) who have this kind of intelligence and who are used to being the smartest person around.

I can tell you that your feeling of wasted potential isn't just a consequence of how you were treated. Most people in this situation have it. Even when they are wildly successful by any other standard. Like PhDs from ivies are normal, the number of people walking down the hallway who are billionaires is astoundingly high, etc.

You would be shocked at the self harm, depression, and suicide rate that at this level. All because of this idea of "oh, I could have won a Nobel" (I'm certain that if they had they would find a way to be sad about wasted potential anyway).

The solution is therapy. Don't wait. Just go do it. Just because you're smart doesn't mean that you don't need that kind of help. It might mean that you need it even more!