PLEASE HELP

so my boyfriend and I had sex 2 days after my period ended, it was amazinggg. And we were having sex without a condom at first but then a couple minutes later he put a condom on. The sex was great my vagina was sore af, but when we were having sex my right side of my uterus was hurting so we stopped having sex. It's 3 days after the sex, and I started spotting, at first it was light pink spotting but now it's brown and my fertile window starts tomorrow. What can it be? And I honestly don't think I'm pregnant because he didn't cum I side me and we always check the condom. (And right now that I'm spotting I feel very sad and tired.