Freaking out about small sex session!

My boyfriend and I were trying to wait until marriage to have sex (he's 21 and I'm 19) and we were doing so good over a year and a half into the relationship. Until last night.

Now neither one of us is a virgin but we wanted to make it special for each other. So we both have not had sex in YEARS but last night we got carried away and did for a little bit. I mean not even 2 minutes but I'm ovulating and we didn't use a condom and I'm so nervous about pre cum getting me pregnant. He wasn't even close to cumming I know that but still how likely am I to get pregnant? I'm freaking out right now!!