pregnant or not ?? help

So me and my boyfriend were doing it or whatever.. he cums inside of me though cause we’ve been talking about me becoming prego but after he cummed inside of me we both instantly regretted it and we went to the store for a plan b , i’m also on birth control but i’m still kind of scared i might be prego?? Is there that possibility of me becoming pregnant ? also yes i have been taking my birth control pills everyday at the same time there’s only been three days where i probably took it 4 minutes late but i’ve only been on it for almost two months. - please help!!