Need Reassurance

So this has been a topic of discussion for a while by on the last few days of my period I had sex and he accidentally came inside of me. It wasn't until eight days after that I started to ovulate. I looked at my chances and my period is supposed to start next week. I know it is nearly impossible giving the chances that I have but has anyone been through this? Also please don't tell me to use a condom next time or to take a test, because I know I was being stupid when I did it.