How likely am I to be pregnant?

I posted about this before but I need some reassurance. Boy and I slept together, lost the condom. I found the condom inside me 17 hours later. The opening of it was outside of me...I guess I just didn't notice it until I showered that night. He didn't finish inside of it (pulled out about 15 seconds before he finished and must have slipped the condom off inside me and not noticed). This was 2 days after my period ended. This was my first period off of birth control after 3 years of being on it. I'm expecting my period next week. How likely do you think it is I'm pregnant?