Well, have to chime in again because you are really going overboard on this trepidation. Since you do not drink, I will not recomend walking/driving to the nearest liquor store and buying your favorite beverage. Or maybe you can, most liguor stores also stock water, soda, etc., for mixers if nothing else.

And a liguor store has the advantage that the guy behind the counter wants your business, and you will NOT be the most oddly dressed person he sees!

If I can give no other advise (again), just do it. Not in a Nike way, but because all of the fears are in your own mind. For an analogy, did you ever go skinny dipping? Were you nervous? did you go anyway? Did anybody say anything? So, same fears and same result.