Anybody have this problem? TMI AHEAD!!

Ok this is a new one for me. Serious TMI ahead. I just attempted to have sex after like a month. Have been on nexplanon since June 2014 and just had the worst experience ever. I had brown clumpy discharge while having sex. No indication of it before hand. Needless to say things ended early and this was just a guy I bang every now and then. We used a condom. When we had sex last month we didn't use a condom one time and I got a bad yeasty that cleared up within a week. Has anybody had this happen? I don't know what this could even be.
I'll add o haven't had a period since December 2015 and before that since the implant was placed. Anybody out there had this happen?