Could I be pregnant? Tmi? Please help

I've been on birth control for 4 years now. I had unprotected sex in the middle of my cycle multiple times in a day. I got what I think is my period yesterday. It's very light and a pinkish color and also brown. I can go with out, but I've been using tampons and it doesn't even get half way full. Could I be pregnant? I've had lots of pains in my uterus and lower back. I've also had headaches, stronger sense of smell, and naseua (no vomiting). Before I got the bleeding I had yellow discharge with red dots. Is it possible? I never miss a pill. It's just really abnormal. I am supposed to go back off the placebos Tuesday and am a little worried to go back on them if I am. Should I take a test? Please help. Thank you. ❤️