Am I at risk of becoming pregnant?

I'm on my 2nd or 3rd day of my period so last night my boyfriend and I decided to have sex for the first time, we didn't use a condom though. He pulled out a couple min before he was about to cum so I know there wasn't any of that but I don't know if there was any pre cum. He was only in for a couple minutes so I don't know if I should worry or not.