B complex and magnesium are the most important now. And fish oil if you don't eat fatty fish often. Also, extra thiamine won't hurt...
For a total recovery based on diet and supplements, I would recommend this book:
https://www.amazon.com/Seven-Weeks-Sobriety-Alcoholism-Nutrition/dp/0449002594
Also, this might be helpful: https://www.amazon.com/Seven-Weeks-Sobriety-Alcoholism-Nutrition/dp/0449002594/ref=cm_cr_arp_d_product_sims?ie=UTF8
16 years since I had a drink.
What seemed to be the key for me was getting an understanding of the relationship between cravings and individual physiology. There's a book, Seven Weeks to Sobriety, it's a really good starting point. I gave my copy to my sister, but if I recall, there was a list of facilities that employ that approach somewhere in the book. (Can't for the life of me remember the name of the facility I went to...)
If this approach seems interesting to you, I would strongly recommend you find a facility that employs this approach, instead of simply reading the book and having at it. There was a time in my life when I thought I didn't need an actual expert, because hey, I can read and figure things out for myself, but the things the nutritionist at this facility knew to ask me about (which went far beyond the information contained in the book) made me realize that reading a few books after work is no substitute for years of training and education...
Also, have you heard about Baclofen? If not, read this article for an idea of the current view on it. Then google it for lots more.
Lastly, for a support group that is an alternative to AA, check out Secular Organizations for Sobriety/Save Our Selves. I went to these meetings for a year when quitting drinking. People who choose these meeting over AA are seeking and supporting total abstinence, just like AA, but without relying on the higher power concept.
(You don't say you have a problem with AA, only that you've been to 100s of meetings and still have a problem, so maybe this isn't relevant for you, but might not hurt to check it out...)
SOS links (google it for lots more...):
http://www.cfiwest.org/sos/index.htm
Edit: OK, read a few more comments, so you do have problems w/ AA... My SOS group (in California, the Bay Area), was not sad old men, I was a 37 yr old single mother with a 5yr old kid when I went, and I fit right in. As mentioned, I went for a year only, and still don't drink 16 yrs later, so it didn't turn into substituting sitting a room for drinking, but even if it had, wouldn't have been so bad, because the company was congenial.
Edit #2: I'm not diagnosed with GAD, what goes on for me is that I'm often really self-conscious, really dislike open ended interactions with strangers, I don't know if that's anything like what you feel with GAD, don't know how old your are, but it's gotten much better for me as I've aged, not much of a problem now, I'm 55.
Alcoholic and cig smoker, non-drinking for 19 yrs, non-smoking for 18, both of which accomplished after 5-6 attempts each, varying degrees of success ranging from a couple or three months at a time to 2 yrs before relapsing on cigs.
I went to a place (outpatient) where they combined straight counseling with nutritional counseling. First visit, 2 or 3 hours were spent being interviewed by nutritionist specializing in addiction treatment. This guy had extensive, in-depth knowledge of so many different ways individual physiology could put us at risk for relapse, it was really unbelievable.
Based that interview, I was put on a bunch of vitamins and other supplements, and even better, learned a LOT about what makes cravings worse for me, and what I can do to help myself by minimizing some of the physical causes of cravings.
Don't get me wrong, all this supplementation and new knowledge didn't remove the need for self-discipline, didn't make it a walk in the park, didn't make it so I could skip over the work on myself, my thinking, my beliefs, etc., that we have to go through to become people who can live without using.
But, I'm not sure I could have succeeded in the mental/emotional work if I hadn't had this "assist" with the cravings.
If you're interested in this approach, there's a book called Seven Weeks to Sobriety (They sold this book at the place I went to because it was right in line with their approach).
And if you google the book name (instead of clicking the link above), you'll get a bunch of links to treatment facilities and programs that employ this approach.
Anyway, I hope this helps - Good luck...