No rude comments please i'm really confused.

so I was on my period 2 weeks ago and my bf came in me, but the chances of getting pregnant are low ( I know there's a possibility but a low one) which I understand, i'll be happy. Yesterday we were @ a party and well we had sex and it was real quick ( few seconds) bc I had to use to the rest room 😂 but we had been drinking a little so i really dont know if I should take plan B? Would it affect me if I were already pregnant? Or should I not take it? bc It lasted maybe a minute at most.. bc I had to pee.