Is It Normal To Have Thick Brown Discharge After Intercourse?

I've been having this thick brown discharge for a few days now, after having sex with a well endowed guy. We used a condom, and I've also been on birth control for almost 7 years now. I did start my pack for this month a day late, and I missed a pill four days into it, but I took that pill as soon as I realized I had missed it, less than 12 hours later. In the last few weeks, I also got my first yeast infection. What could be causing this discharge?