I quit drinking recently (just hit a month wow), and so far it's been fine because I'm spending all of my time alone or working/doing errands. I don't like drinking alone so it's been fine, but where I live now the ENTIRE social scene is bars and clubs, so I can't meet anyone without being sober in a room full of extremely drunk people. I don't like clubs to begin with, and there's not really any quiet, sit down pubs around here where I could just get a soda and relax.
I used to pound drinks with my buds, but now that I'm seeing demonstrable health benefits of quitting (I have epilepsy and alcohol was giving me seizures) it's getting less justifiable to consider drinking again. I could smoke weed but it often makes me quiet and awkward when alcohol makes me outgoing and confident, which is what I really need right now. Also weed makes me shit at darts and pool.
I really wish smoking didn't give you lung cancer and all the other diseases because it's such a great excuse to leave an uncomfortable situation.
Just leave and go outside to stand with the smokers. Being a non smoker doesn't mean you can't go out and talk with the gang, "just needs some air" otherwise. It's all good.