Welcome back blondescorp. I agree that focusing on now vs the past is a good idea. It's OK to look back a little bit to see if you can learn from the experience though, right?
You'll want to ask yourself what you could have done differently. For example, why were you hanging out with a bunch of drinkers in the first place?
I've found that for the most part, people really don't care if you are drinking or not- in fact most people don't even notice. It's our alcoholic minds that obsess about what other people might infer from us not having or accepting a drink. "no thank you" is all you really need to say probably 99 percent of the time.
So start working on a plan for next time this situation arises - maybe your solution should be to just avoid obvious drinking situations and people you know will push a drink on you?