Do you have a friend you can talk to? This is so important to do to help you with your worries and all the other emotions these things trigger.

When you get your period, you will stop worrying as much. In the meantime, if you have not gotten your period 2 weeks after this encounter, at that point you could pick up a cheap pregancy test to calm your fears.

Did you blackout? If you did then your fears are quite rational. I can relate to going through these things over and over again in my head. Hang in there. It will calm down eventually.