I am not no physician, but I had the same problem you have. The pains hurt so bad, I was physically unable to do much. When I went to the doctor he found out that I had uterine fibroids. It caused the heavy bleeding. But also, later down the road, painful cramps and heavy bleeding returned. It was not anything serious. I needed to exercise more and eat more healthy. It helps the blood to flow more better, and this will also help the cramps since they are caused by the blood flow being heavy.