Me And My Boyfriend Have Unprotected Sex Often. Even When

Me and my boyfriend have unprotected sex often. Even when I'm on my period. Recently, my boobs and Back ache and when I use the bathroom, there's blood - not period but just a light pink. And also diarrhea. The aching just started but the other has been going on for a couple of days, not to mention how frequently I peed today. Why is this? ..I had my period about two weeks ago so it shouldnt be that.