My girlfriend is experiencing a brownish/mohogany discharge and burning in her vagina. She is not on her period. We had unprotected sex while we dated, because neither of us had sex before and she was on the pill, so we had sex like this every time. We broke up, and she had protected sex as well as I did one time. Now, two weekends ago, she and I had unprotected sex again frequently over the weekend. What could this be from? We used to have regular sex before I moved to college, and now we did a lot over that weekend. What could this be from? She also took a plan-B one step pill right after we had sex over the weekend. Help?