Bloody diarrhea, should I be worried?!?!?

So, I bumped pretty hard into a doorknob ealier, near my pelvis bone on the left. 1-3 hours later, I had stomach pains. I got runny diarrhea. It didn't just have blood in it, it WAS bloody. It scared me D: Oh, I recently got off my menstural cycle/period. Should I be worried?