Help! Stopped taking birth control in the middle of a pack but confused?

I recently started taking birth control again, and after I was about halfway through the pack, my fianc� and I had unprotected sex. I continued taking birth control, but it was making me increasingly nauseated and very very sick and I started to have breakthrough bleeding that wouldn't stop. So after a few weeks of this, I just stopped taking it. I can't miss work and of all my activities because of a pill... But now I still haven't stopped bleeding. Can someone explain what my body is doing right now, or if I may be pregnant?