I am a 19 year old that has been on birth control for about 4 months. I am sexually active, but me and my boyfriend always use a condom for the additional protection. About a week ago I started having really thick brown discharge. It is enough to stain my panties, and it is constant. I am supposed to start my period tomorrow, however I usually have really sore and tender breasts but they havent been that sore. I am kinda scared that I could be pregnant, and I was just wondering how likely it could be. The brown discharge is just throwing me for a loop.