Help please!

I’ve been taking the pill for many months now and I always get a period. I’m mostly perfect with taking it (most I’ve ever been is 2 hours off). This past month was one of the most stressful for me ever, but that usually hasn’t affected my period. My boyfriend and I had sex probably 4 or 5 times this month but he uses a condom every time and pulls out much before he cums. This week was my period week and I only got 2 days of a small amount of brown discharge which is unusual for me. My gyno switched the generic brand I was using, though the dosage/hormones are still the same so I would hope that wouldn’t compromise the effectiveness of the pill. Is there a chance I could be pregnant?