When I first admitted to myself that I am an alcoholic, I was TERRIFIED of being around the people who always knew me as the guy who wouldn't turn down a drink, and would pretty much do anything after having a few in me. Surprisingly, when I "came out" about my decision to not drink any more, I got a TON of support from the people who truly were my friends, and after that initial first awkward conversation, it was over and done with.
Sure, there were a few relationships that I had to terminate, they were no longer healthy for me, but in the overall scope of life, those relationships were based on alcohol, without it, we didn't have nearly as much in common.
Don't be afraid of making this decision, I am confident that you will find more support and love than you anticipate, and if you find the opposite from some people, it may be time to reevaluate your relationship with those people.