Unsure pregnancy

I’ve been feeling off lately and honestly I’m worried I may have conceived. It was unprotected sex a day after my period Christmas week - I am on birth control - but I would have to wait until my next period before knowing for sure, which is still two weeks away. Every day my stomach hurts and I’m nauseous, and it’s already been two weeks, so it’s too late for plan B. Honestly I’m terrified.