If you've never had sex before, you could not possibly be pregnant. Symptoms of pregnancy are actually very subtle and don't show themselves right away. And what does show, it's just like pms. So, it's probably your hormones doing their thing causing any symptoms you have. If you fear pregnancy when you haven't had sex, I'd possibly talk to your doctor about anxiety. Because that would not really make sense. So, working on the anxiety would make sense.
This is all in your head, trust me. If there was no penis involved, there's absolutely no way you could become pregnant. I wouldn't stress. You cannot be pregnant. Just take a chill pill and relax because stress can make your period late. Don't worry :)