I always have unprotected sex with my boyfriend and I have been on the contraception pill for about 8 months. Last week, we had unprotected sex as usual and three days later, I started to notice that I had brownish/pinkish vaginal discharge. I got tested out negative on STD's tests six months ago. I am pretty sure he cheated on me and catched a STD because he was complaining about pain while he was having an erection... I am going to go see my doctor to get checked but while I wait for the appointment, I want some opinion about what could be the cause of my brownish discharge...