TMI! WHAT IS THIS?!

What is this?! It's like brown clumps that look like tissue but I have no idea at all. I know it's definitely not my period, because my last period was from June 12th-16th. Last time I had sex was Thursday June 18th two days before me and my boyfriends (now ex) anniversary... we broke up recently and I haven't told him about this because I didn't want to freak him out. We had sex twice within the span of about 2 hours that day, before and after we ate dinner, and we didn't use protection but he pulled out both times. He came on the backside of my leg and it kind of dripped down onto my butt for a split second, luckily I grabbed a nearby napkin to wipe it before it got any further. Please help!