Period and Sex

So my boyfriend and I had sex on Friday, and without protection! At first he told me he wasn’t sure if he came or not, then later he confirmed me telling me that he for sure didn’t. But yeah, I was supposed to start my period on Monday. So three days after we had sex. The first day of my period, I bled a little, it was brownish and reddish. If wasn’t really like spotting, to me it seemed like period blood. But then after that day, it stopped. But before all that, I had so much stress going on, major stress. Especially the day after we did it. Like right now, I’m very stressed. Did my period stop due to my major stress? Or?