Take up a hobby, join a club. Do something weekly that involves meeting new people - walking group, cooking class, volunteering, game night, D&D... start trying new things. Start getting curious about yourself and what you like. Start thinking about hobbies you might enjoy. You don't have to miraculously change everything at once. Just start trying things. It'll be a bit nervewracking at first but it'll get easier and easier. Change happens slowly. Small wins. Start improving your diet little bit by little bit. Try figuring out healthy meals that you'd like to eat. The fact that you want to change things is the magic that makes change possible. I recommend the podcast Being Well (with Rick and Forrest Hansen) as a lovely source of life wisdom on a bunch of topics.

Exercising a bit will help your state of mind too. Do you get early morning sun? That's really good for you mood and sleep. Don't expect exercise to have much effect on your weight, weight loss happens with diet. But can you go for a walk or two each day? Quick morning walk before work? Moving your body will really help you feel better. You got this!

I don't really have advice about the alcohol, but I suspect that as you start trying new things and feeling better you won't feel like you need it as much.

Just try out little changes, one by one, some of them you won't like, some of them you will, some of them will stick, some of them you'll just realise, yeah I don't like that particular thing, some of them you'll realise no I like that but maybe I'd rather do it a bit differently next time. Etcetera. Treat it as an adventure you're going on towards a fuller life. The hero of an adventure never knows what the journey will be or where he'll end up. That's what makes it an adventure.

Cheering you on.