3 weeks without BC pills, could it be?

I quit taking birth control 3 weeks ago, at the start of my period. On cycle day 8 we had unprotected sex. Since I've been on BC for 10 years we have expected it to take a while for a normal cycle to emerge. I ovulated around cycle day 13, and now I'm feeling nausea, sore/larger breasts, weird dreams. Is this normal for getting back into a cycle or could I be pregnant?