I think I have pcos I have tried dieting, and birth control, and I really don't know what else to do. I have not had a menstrual cycle in almost over 6 months not when I first got on birth control I had one maybe a month later for 2 days. Any advice?

Yes, I have advice:

Go see a gynecologist.

There are waaaaay too many reasons for not having a menstrual cycle--some of them extremely dangerous.

I have PCOS, and I sometimes WISHED I didn't have a menstrual cycle, because it was extremely painful to ovulate.

You are trying to self-diagnose and have no idea what is really wrong.

Go see a medical professional to get truly diagnosed.