Miscarriage?

So I'm 18, in college, and recently started seeing this guy. It's been almost two weeks since we had sex the first time (it's been a while since I've had sex) and now I'm experiencing brown and bright red discharge two weeks before my period is supposed to start. I'm on the pill, which I take on time all the time, and we used a condom, but I'm nervous because this is way to early for me to have a period and the cramps are awful. I've been on the pill for 5 months and I recently started taking antidepressants. Any advice?