getting nervous about my nipples

I have 3 days before AF is supposed to start. for about 3 days now my nipples have been dark red and erect, sometimes sore. they only get sore before AF, but never red and erect like this. and I'm not sure but I think they are a little bigger too. no change in my areolas though. I'm getting nervous thus I could be pregnant. my boyfriend and I had sex a few days before my firtile window but we used a condom. I think it was slipping during. it didn't come off completely or break. what do you think the chances are that I am pregnant, and did any of you get thus kind of sign before the BFP?