Period sex on birth control

My boyfriend and I recently had unprotected sex while I was on my period last week. I take my birth control religiously but this was the first time I’ve ever had period sex (I was very light). This week, I’m not sure if it’s just anxiety or what but I feel like I’m nauseous (but haven’t thrown up) or bloated after eating. Could I be pregnant? Has anyone experienced this? *No, he did not finish inside.