Why am I not getting my period?

Sounds like sports induced amenorrhea. Common. Caused by a lot of exercise. How long has it been since you've been on the pill. Despite your negative reaction to it, it might be worthwhile to find a different pill, one that doesn't cause all those problems. This is because not having your period for awhile at your age is very bad for your bones, and can cause lifelong problems with bone strength. See another gynecologist--one who cares about you and will treat your problem.