What's wrong with me?

My boyfriend and I are at separate colleges this year, I went to visit him last weekend and of course we got busy in bed.... I'm on birth control, but after our visit this month I have been experiencing diarrhea and heavy amounts of creamy discharge. I visited him again this weekend and while we were having sex there was a hint of blood in my discharge. We tried again the next day and I experienced a slight discomfort as he was inside of me and yet again a hint of blood. My discharge is now a light pink color and I have been experiencing back cramps and slight stomach cramps. Any idea as to what might be going on with me? Any advise would help. Thank you.