Mid-month discharge?

Okay so this is probably TMI- but me and my bf were having sex last night and I noticed I was really wet before I was even horny. So we had sex and when I went to get dressed, I noticed brown goo in my underwear.. My bf never mentioned seeing any "down there" and my period was about 2 weeks ago. I'm on the pill and I've had bleeding mid month before but never this brown stuff. Any ideas??