First and foremost, go to the doctor. Period (no pun intended, really). Only they can diagnose the problem. I would also suggest asking them to test your blood counts to see if you're anemic (although I'm sure they'll do that automatically).
I had a similar problem when i was in high school, and my OBGYN put me on birth control. It eventually resolved. However, I HAD to see a doctor. What you're describing is alarming and needs to be evaluated ASAP. If you can get an appointment with a gynecologist without seeing your primary care doctor for a referral, go straight to a gyno. Otherwise, your primary care doc should be able to help you.
Just to repeat myself, get your blood counts done as well as the hormone and thyroid tests I'm sure they'll run. I am not a doctor, but the fatigue etc sounds like anemia to me.
