Hi bikini and welcome to the forum!
I don't know anything about alcohol substitutes (unless it's something like non-alcoholic beer or wine?)
If you have a problem with alcohol, the best thing to do, obviously, is to stay sober. Most of us have tried to control or moderate our drinking and failed to maintain it. Christmas parties can still be enjoyable without liquor, and besides, that's many weeks away.
The best thing to do is focus on staying sober one day at a time. Keep reading and posting. If we can do it, so can you!
