I have been sexually active for a little over a year, and this past February began taking a birth control pill (Ortho Tricyclen-Lo). Recently I returned to college, which was slightly stressful. My last period began August 5th. I had sex with my boyfriend the 27th of August, and we did not use a condom. I took my pill late that day, too. Now, a day or two before my period, I had some spotting (red blood, lasting under an hour), and some pale brown discharge (which I believe is just a little dried blood). The chances of getting pregnant are low, right? Is this just due to stress?