I'm scared I might be pregnant, help...

About 10 days ago, probably around July 13th I had sex with my current boyfriend, we used a condom (like always )and he came in it. After that,I didn't see when he took it off, but he did and we continued having sex... I realized a bit after that he didn't have it on and I got mad, I told him to never do that again and he apologized and promised to never do something like that. I'm very careful when it comes to safe sex because I'm not ready to have a child and I get paranoid very easily... but now I'm 8 days away from my period and I've been having sore nipples for a few days , I normally have sore breasts before my period, but almost never have sore nipples, I'm starting to get scared, please someone give me some advice or peace of mind I'm very anxious right now... thank you for your time.