freaking out

Right okay so I have a kind of problem, I have the tendancy to extremely over react however this is an actual serious thing...

I am on the pill I had my period on the 8th - 11/12th of January, then I started taking the pill on the 14th. However I had sex ont the 18th(unprotected sex blah it was a spare of the moment thing) and that morning I had forgotten to take my pill like I normally do. I took 2 in the evening as soon as I realised but oh my god I am freaking out thinking I am preganant. What the fuck should I do? I have to wait 2 weeks to finish taking my pills to see if I miss my period. Ahh!!!

Please bare in mind it lasted literally like a minute or two and he pulled out. I know I shouldn't freak out because what are the chances, but I can't help it. I want to vomit thinking about it :'(