Pregnant?

My husband and I decided we wanted to soon try for a baby so I stopped taking my birth control last month. We've been pulling out for now because we wanted to wait a lil closer to January. Well out of nowhere I got super nauseous tonight and fatigue so I figured I'd shower. After I showered I ended up throwing up. My period is expected to come this week but could it be possible that I could be pregnant from the precum?