Help!!! I’m so stressed

So I’ve been on birth control for a REALLY long time now and I’m really good at taking the pills on time. My boyfriend and I had sex the day I was supposed to start my period but I didn’t start that day and he said felt like he came in me but he wasn’t sure! I started my period the next day but I only bled like two drops a day and it lasted 4 or 5 days. I’ve also been having lower abdominal pain & I’ve been nauseous a lot lately. I know there’s a chance I can be pregnant due to the fact I had unprotected sex but idk!! I’ve had so much anxiety lately. /: Thoughts?!