I had sex with this guy aug 23 and we used a condom and he did not nut in me and than my period came on that same day I had a regular period and than I had sex the beginning of September and in the middle with my boyfriend is it possible that I could have gotten pregnant sept 15 ? Because he said when we had sex the beginning of September he did not but in me but we never used a condom

Yes. It's possible. Nut? I hope you have more self respect than that.