Excuse me - I'm going to take a tremendous liberty here and post, will delete it if it strikes a false note. You see, I'm not an alcoholic, not even lying to myself, I'm really not! (Got a few habits we won't talk about but they're not alcohol or drugs.) Every now and then, though, I like to read this thread because it is so totally uplifting to see fabulous women - and men - grabbing a new lease on life. Even those who slip, admit it and start again, it's triumph of the human spirit stuff, you're great people, and I expect there are many others who don't have this precise problem who read and cheer too. So I read it this morning, and a couple of thoughts occurred which might be helpful - or annoying. Hence my tentative approach.
You talk about going to a social event and how very very hard it is to refuse a drink. Because you don't want to refuse it, I get. But because people will notice? Er no, sorry. That one is bullshit. Put it on the "reasons to drink" list along with it's raining, it's sunny, it's term time, it's the holidays and all those excuse you don't buy any more.
Sometimes I'm driving or on medication or (years ago) pregnant, or even not in the mood for booze. On such occasions I say "I'm not drinking alcohol today" and reach for the orange juice. There are only two ways other people react to this. Most will say "ok" without much interest. A few, possibly pursuing their own agenda, will press you on the grounds that "one glass won't hurt". The response that works for me is to smile brightly and repeat in exactly the same tone of voice as before "I'm not drinking alcohol today". I wouldn't generally go into the reasons why I'm not drinking, it's not something one needs to excuse. (It could be "because I'm an alcoholic", but that's none of their damned business is it?) It is a very rare, very rude and probably already drunk person who will push it further, and who wants to oblige someone like that?
It isn't easy to say no, of course, because you want the drink. That is the issue. Whether you really want this drink more than you want to stop. What "they will think of you" though, that is a complete non argument. Most people don't judge in that way, and those who do have their own problems imo. Maybe you'll do them a favour by showing them what a person having a good time without alcohol looks like. It may make them look at their own intake with a more critical eye, who knows? Not that it matters really. You're responsible for your own drinking, not for theirs, any more than they are responsible for yours. It's no good claiming they made you drink by, er, being there seeing you not drinking!
I guess because you've been in that habit some people described, of comparing your own intake with other people's, you assume everyone is doing the same, so how much you have will be of great interest to them. Actually, for those whose life doesn't revolve around alcohol, really, we couldn't care less what you have in your glass and actually not all that bothered what's in our own, as long as it tastes ok. Maybe if it was exceptionally nice and some greedy swine swiped the last of it I might be a little miffed, just as some people would be cross with me for having more than my fair share of the blancmange 
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God that sounds patronising, and it so isn't meant to. Just thought the perspective might be helpful.