pain a few days after sex

Hey I need yalls advice! Every once in a while, a few days after sex (or even sometimes when I haven't done anything in a while) I get these really bad vaginal pains. They are usually a few days after sex and the best way I can describe the feeling is kind of like burning. I'm having it right now and really really small clots of blood are coming out. The pain lasts about 2 hours and it hurts to do anything. Does anyone know what's wrong?