Welcome!
Interesting story!!! I'm not sure I see the problem? Maybe I should read again. You're not an alcoholic but the only friends are at the after work bar. Would you mind hanging out with them and just NOT drink yourself? Is it possible?
As far as learning how to have a successful relationship and how to deal with people at workplace and elsewhere is a life long journey. You learn these things as you get older.
I often say to myself, I wish I knew 20 yrs ago, what I know today. But hey, it didn't happen. I'm still very grateful for my experiences in life, all the choices, and how I am now as a result.
WELCOME and
Best wishes to you!