Had you had irregular periods before you started your diet? Many years ago when I was 35%+ bodyfat (16% now), and I first began working out and making dietary changes, my periods went crazy. I wouldn't bleed for three consecutive months, then I'd bleed for ten days straight, or have a period every two weeks. It could just be that your body is reacting to the "stress" of working out and shedding bodyfat that it "took for granted".
...But yeah, definitely haste ye to a gynecologist as soon as possible. There's a cornucopia of problems that can occur with the female reproductive system. Better that you stay healthy enough to have the luxury of dieting, than ignore a potentially serious problem and have to go on medication to correct it, and not be able to maintain your diet and excercise. Good luck, and keep us posted.
Spoke to a doctor today. She said not to take the Provera and to get a shot of Lunelle (my usual birth control shot) tomorrow to stop the spotting. I didn't get it on Feb 13th because I was still spotting from my period that started on the 1st, so i figured things weren't working right in my body. She said that this extended spotting thing was a side effect of Lunelle that she had seen in another one of her patients and that when her patient gets the shot everything goes back to normal. Fine with me...this provera the school nurses prescribed is making me puff up and feel like a chunk. The school nurse told me actually that the provera should make me have my period AGAIN in a few days and that this was a good thing and not to take Lunelle for atleast one cycle. ARGHHHHHHHHHHHHHHHHHHH Lesson: Never go to the school nurses for anything other than a head cold.
Oh yes, and CEEB asked if the diet could have caused it. Nah, eating healthier didn't do it.