IUD fell out

My mirena fell out and my bf came in me several times during the period of which it could’ve fallen on. My obgyn said that the bleeding I was experiencing was from it falling out, and put me on the pill the same day. I bled for a week assuming it’s a period. However I’ve been extremely nauseous, hungry, and tired lately. I’m scared I could be pregnant? Or could it be a side affect of the pill?