Pregnant?

My boyfriend and I were having sex and our condom broke. We stopped then because I'm not on the pill. He hadn't finished yet but we had been going at it a while and he usually has a lot of precum. I'm wondering what the chances are of me being pregnant because it didn't just break a little, it like completely busted. Plus, it was one of my fertile days. It's not time for my period yet so I wasn't going to take a test just yet.. Any opinions? Has this happened to any of you?