alcohol and pregnancy

The guy I've been seeing have been having sex regularly for the past 7months and I'm not on birth control because I smoke cigarettes. We are also not a huge fan on condoms LOL. Long story short he came inside of me a few nights ago. I took plan B after 5 days (which I know is super late) but I thought it would be worth the try. Now I'm having very weird sensations in my stomach, I get nauseous whenever I eat and my tolerance to alcohol is insanely low. I'm not a huge drinker, but I never get hangovers, however now I'll drink one or two beers and wake up completely hungover and unable to function for the entire next day. Could I be pregnant?