My signature drink is water, no ice, no straw, and a few lemons.
You're experiencing social pressure to drink, so that means that you're letting your environment dictate how you feel.
It is my personal belief that drinking alcohol for the sole purpose of fitting in or because you can't do something without it is
accepting that you are mediocre, and that you need to change your body chemistry to cover the fact that you essentially suck. That being said, I'm going to an art gallery opening tonight and drinking free wine, only because it's free and I'm not going to game
If people judge you for not having a drink in your hand, see the above in bold. I have NEVER had anyone tell me that it's weird that I'm drinking water, or ask me where my drink is. Sometimes I'll roll around with my water because I get thirsty from talking so much, plus I have a fun little routine I use with the lemon slices to kiss a girl.
If someone asks, just tell them that you don't want to drink. If they ask why, just tell them the truth; you're driving, you don't feel like it, etc. I personally don't do it because of the reasons I just gave as examples, plus I don't enjoy how it affects my body, and I don't really need alcohol because I'm already f*cking awesome without it.