3 Day bleeding

I had a period 2 weeks ago and before that had unprotected sex I believe a week or a few days before that , than this past Tuesday happened again. On Thursday woke up to like a period it wasn't to heavy but it was more than spotting , I googled what could be the cause of it , and one if the reasons stated it can be from rough sex , it lasted like 3 days !!! Have anyone ever experienced this or have any thoughts on what can be the cause ???