Highlighter Pink Blood

Last month my period was extremely painful and my period blood reminded me of a pink highlighter. It only lasted for three days. Motrin didn't even help the cramps and they also lasted for three days.  Both are very unusual for me. I only had this happen once before in October of 2014 except I didn't have any cramps. That was after a bad sexual assault. What could it be? What does it mean?