Hi,
i'm 17 years old and also had an irregular period. I ate absolutely healthfully and exercised as well (biking, swimming, dancing, zumba), took birth control pills after i got a pelvic exam, but nothing worked. I lived quite stressfully that time, and my girlfriend recommended me hatha yoga for calming down and relaxing. It really helped, and I don't know why, but since i'm doing yoga, my period became regular again! o.