Chance of pregnancy? Help

I need some help and reasurence for other girls. So on Saturday even my boyfriend and I were fooling around. While he was atop of me kissing he stuck his penis inside me for about a minute till I freak out because of pregnancy on my glow it said 27% of prgnacy. My period started on nov 6th and ended on Sunday the 9th. I have the very short unprotected sex on the 15th. He never cummed and said he doesn't know about Precum. Does Precum even have sperm?also I was taken off bc in October and have had regular periods. Do you think I have a chance of getting pregnant or very slim to nun? I know it was a stupid mistake but I need someone to educate me and let me know if I could be fine.