Can I be pregnant?

So in January I had unprotected sex. The guy didn't cum in me but some might have. I did get my period but 6days late. This past week I've been feeling really nauseous. I know I'm probably being paranoid and overthinking this but I've read that some women can get their period that first month and still be pregnant. If I don't start feeling better by next week I will take a test to make sure but I want to know your opinion on this.