HEAVY spotting after sex?

My boyfriend and I had really rough sex two days ago, and I was spotting a little bit afterward. Yesterday it was a little bit heavier, but I could still get away with just wearing a pad. I woke up this morning with that "I NEED to change my pad" feeling and the bleeding was even heavier, as if I'm actually on my period. Except my period ended five days ago, so I doubt it's back already. Has anyone else had such heavy spotting from sex?