Help please

So on the 11 me and my boyfriend had safe sex and we used a condom. When switching positions we were trying to keep going but he’d fail and when I looked back I saw that the condom was already full. I immediately got away and got super scared. My period should have been today the 14(according to the app) but sometimes I’m either too early or late with the app like sometimes it will get it right. The app said I had low fertility on the 11th. I’ve been told by my friends that I am not pregnant but I’m still scared. Am I safe? Or is there a chance I might be pregnant?