Could I be Pregnant????

My fertile week was November 1st-7th . My fiancee and I had unprotected sex most of that week and the week after. Lately I been feeling a little nauseated. I threw up at class one day and my lower back has been hurting. I don't ever really have back pains at all. My cycle is due today but I don't feel any symptoms of it like I usually do. Could I be pregnant?