Advice please don't judge

Ok this is kinda embarrassing to talk about so please bear with me. Me & this guy had anal sex & he ejaculated in me. A few days later he texts me asking if I was absolutely sure that we did anal bc he's worried that I may get pregnant. I assure him we did but I just wanna hear what y'all have to say. When we did it, it was 3 days after my period had ended so I wasn't in my fertile window yet. Any advice that can get me to relax?