could I be pregnant?

I'm freaking out that there is a possibility that I could have gotten pregnant. I didn't realize at the time that I had cum on my hand from the guy I'm in a relationship with and then I started touching myself. Now I'm freaking out that it could have been enough to get pregnant. Everything I've read says there's always a possibility but now I don't know what to do. My period isn't due for another two weeks but for some reason I can't stop thinking about what if? Does anyone have any advice on anything that could help?