I have horribly heavy , long and very painful periods. They usually last up to two and a half weeks. When I was on birth control they lasted more like 1 1/2 months , I would start a few days before the placebo pills. I have l always had large clots that come out while I'm having my periods, just wondered if anyone else does or if this means I have endometriosis. I have always had horrible periods, and I was 10 and a half when I started. I was diagnosed with pmdd when I was 15 and also had a ruptured cyst. I have been on different types of birth control pills and the shot, but my body does not tolerate any birth control. I have been off of any since November.