How Can Painful Menstrual Cramps, Irregular Periods, Nausea And Clotting Be Treated?

I had a tubal ligation and have been getting very painful menstrual cramps again like I use to when I was a teenager and my periods have become irregular what can I do. I have tried laying down with my legs curled up to my stomach, I've tried taking a hot shower, I've taken excedrine extra strength and midol I've walked but it seems to be hard and I feel nauseated and the blood clots have been very dark in color but a bit bigger than a quarter. Please help me.