Late?

A few weeks ago my boyfriend and I got drunk at a party and TRIED to have sex. He couldn't completely fit because it would have been the first time for me in a long time. But we still tried, and without a condom. I am now two days late. And I'm starting to freak out. I'm 18 and a senior and don't know what to do. Should I take a test now or wait a few more days? I am on birth control so maybe that is why I'm late?