The most important vitamin in withdrawal is B1 (thiamine), as lack of it can cause 'wet brain'. You may be deficient in B12 and other vitamins too, but it is very important to supplement with B1, as it won't work retrospectively.
If you think you have a habit rather than an addiction, my advice (based on my own experience) is to find an alternative and keep to the ritual(s) you are used to. I found the non-alcoholic fizzy wine quite palatable, and opened a bottle when I sat down for the evening, pouring it into a normal wine glass, and topping it up over the course of the evening. I continued to go out to the places I went to when drinking, but switched to lime and soda, or plain soda with a wedge of lime or lemon - again, so that I wasn't constantly reminded that I wasn't drinking as I would have been if I'd stayed in every night. Gradually, I started to stay in more anyway - I did lose some friends, but came to realise that they weren't real friends anyway, and don't miss them.
I found hypnosis tracks useful, and listened to them in bed. i don't know if they worked as hypnosis, if the ritual helped, or just the relaxation that they all start with, but it doesn't matter. I'd have a bath, get into a warm bed and drift off listening to relaxation/hypnosis, which is so much better than the half-sleep you get after drinking a lot of wine. Waking up without The Fear is lovely, too. As time goes by you might replace the rituals with something else, or just give them up altogether, but drinking is ritualistic - opening the bottle, pouring the glass, topping it up and so on - so if you still have those things to fall back on it can make it easier to give up the actual alcohol.
Incidentally, doctors don't use the term 'alcoholic' these days, preferring 'problem drinker' or similar. If you see yourself as an alcoholic it suggests lifelong dependence, which is by no means always true. If you break the habit it doesn't have to be an eternal struggle to stay sober. I genuinely don't miss it now, and have had a (very) occasional glass of wine, eg at a wedding, without entering a downward spiral as happens in TV drama. Having said that, I honestly recommend giving up altogether, rather than cutting down, at least at first (I am coming to 7 years since I gave up).
Good luck!