Scared

So 3 days ago my boyfriend and I were having unprotected sex and in the moment I knew he pulled out and I was on top of him so we stopped for a min and without even realizing we were going again without wiping it off. I am on birth control and I take it everyday at the same time but do you think I should go and get a plan b today. I know it’s already almost been 72 hours but I really can’t be pregnant because I leave for college in August. Someone give me their opinion please...