EA-6B1, I have not been in the Marine community, however when I was consulting we would go drink every night after work. There was one guy with us that did not drink. We didn't think anything of it, he would get Sprite, we would get beer, no big deal, and guaranteed DD, so that was really cool. Just don't make a big deal about it. I have also jumped on the wagon a few times, went 4 months last year without a drop of beer, and I would still go to the bars and drink water and nobody would say a word. (I just couldn't go any longer without having a beer, so I had to rethink that diet).
I was told in a sermon once, "You know you are doing right as a Christian when the guys invite you to the bar, fully knowing that you are a Christian and knowing that you will act in such a way"
You can still enjoy camredirie in a number of ways (even at the bar), just don't pass judgement and don't bring attention to the fact that you are choosing not to drink. Most men will respect your decision.
Eliminate distractions, focus on your goals and visualize what you hope to accomplish.