Pregnant?

So I take my pill religiously every day at the same time. June 20 I had unprotected sex and he didn't pull out in time. My period is due this Wednesday and I'm starting to freak out. I think my mind is playing tricks on me. My boobs hurt ( but could also be bc of my period ) - have the worst migraine and today I'm super nauseous. Can anyone give me any advice to feel better? Definitely not trying to be pregnant. I mean that's what they make birth control for!! I have never missed any pills but I guess there is always a chance.