Weird cramping.

I got off my period 4 days ago, and I have had really bad cramping the past 2 days. I have never had anything like this before. Me and my husband so not use any kind of protection, but he does pull put always. The day before I got my period we did have sex and he did not pull out. So what I'm asking has anyone had cramping like this after ther period? Does anyone know what it is?