Could I get pregnant?

Yesterday my boyfriend came inside me for the first time in our year+ relationship. On top of that, we came at the same time! I've been ovulating the last few days and yesterday depicted the highest risk of pregnancy per this app. We bought Plan B yesterday and I took it. I haven't had any side effects. But just curious about your thoughts while ovulating and plan B. I've researched via the net, but maybe someone can give me some advice. If an egg has passed and had been possibly fertilzed do you think I could be pregnant or will plan b work?