Tell me real possibility

So me and my boyfriend were being stupid and had unprotected sex. It was only for about 10 seconds. He did ejaculate the day before (10pm) he had peed multiple times throughout the night and next day. The next day at about 5pm, is when the unprotected sex happened. It was for a couple of seconds, no ejaculation. From what I’m understanding, pre cum doesn’t have sperm inside of it, although it can get contaminated if there is some sperm in the urethra, although peeing can help flush it out. I looked at the Flo app, I know it isn’t trustworthy but it gives a ballpark, and it says I ovulated on June 6th, and unprotected sex happened June 8th. I’ve looked at all of my other cycles and a common pattern is that 15 days after ovulation is when my period starts. It says my period is supposed to start on June 21. I’m not ready for a kid yet, I am young and stupid. Someone please help to reassure me although give me the true probability of being pregnant.