Nervous...

I'm due to get my period tomorrow. I had sex at the beginning of November and a condom was used. He also pulled out right before he came (with the condom on). I've had some normal pms symptoms but for the past 3ish days I've also felt slightly nauseous/dizzy? Like a weird combo of eating too much food and feel like I might pass out. A couple times in the past I have felt terribly nauseous when I was ON my period but not before. Could I be pregnant?