Possibly Pregnant?

My boyfriend and I recently had sex. I am on the patch however when I got home I had noticed it fell off. I started my period the next day. My period has gone on much longer than usual and I am very nauseous. Even the thought of some things makes me sick. I gave blood today and usually when I give blood I'm fine, today I blacked out about and hour later. I'm kinda concerned I just might be pregnant. Any advice or comments?