Carla..I had a similiar problem but not to your extent. 2 years ago, when I started biking seriously, no matter where I was during my cycle, if I exerted or heavy hill climbing, I would cramp horrible and start bleeding. Talked to my Gyn who said,,,age related (38) and sometimes that happens... and passed it all of type of thing. Over the winter, things were normal sceduled, no bleeding or cramping with indoor workouts. When biking rolled around in the spring, same thing started all over again. Saw a new Gyn who suggested an transvag ultrasound. Then had a D&C done, she said the inside of my uterus was like a rolling terrain, and described that blood had pooled in the valleys and would "break off" so to speak with exertion. WELL, what ever, it worked for me.. Have you tried birth control pills just for regulation, like a low dose? Hope you make out okay..