What Causes Brown Vaginal Discharge A Week Before Periods?

Lately I've been having brown vaginal discharge a week before some of my periods, I'm on the pill. Recently my boyfriend tried to penetrate me for the first time and only got the tip in with a condom, or a little past and it started to hurt kind of badly so I stopped him. A few days later (about 2 weeks after my last period) the discharge started again and varies in flow. I read somewhere that discharge like that can be a sign of pregnancy and I'm freaking out. Is it normal, trauma or am i pregnant?..