Missed BC pills

So I missed a week of birth control pills and my husband and I had unprotected intercourse once during my fertile time. The day that I was suppose to ovulate I started bleeding, I bleed for 4 days. Now I am suppose to have my regular cycle this Friday. I have been feeling tired and nausated sometimes when I eat. I don't know if I could be pregnant or it is all in my head. Please give me your opinion.