My Fiance And I Have Had Unprotected Sex. He Pulls

My fiance and I have had unprotected sex. He pulls out. The past couple weeks I've had headaches, I am out of breath when I walk up or down stairs, I get nauseous, I pee a lot more, my back hurts some days, my sense of smell is stronger than it was, I'm 3 days late. Could I be pregnant?