Sever cramps AFTER period, watery discharge?

I was on birth control for about 4 months and throughout the entire time I was having problems with irregular and breakthrough bleeding. So after my last pack was complete, I had my period and I quit taking them. Ever since my period has been over I have still been having sever cramps (the kind that hurt so bad they make you nauseous, if anyone else has ever experienced those.) I have also been having a very strange discharge. It is just like water. Clear and it doesn't have a smell. Nothing will get rid of the pain. It is just like very sever menstrual cramps. But I am not on my period whatsoever. Does anyone know what this could be?