Hi. I really feel for you in that situation. Though I can't relate to alcoholism, and I'm at a bit of a loss on what to say about it exactly, I can really relate to the existensial crisis.
My waking up faced me with the same questions, and I've been through some pretty dark times with it.
I can't answer the question of how you can deal with it, just tell you what is helping me. I've come to believe that the lack of a grand purpose for the universe and us is actually quite liberating. We are free to follow our own set of values and do what makes us happy.
In paradise, I was just hoping I'd get to do what I really want anyway. That wouldn't have any objective purpose either. Even if I lived forever, it wouldn't give my life purpose or direction. God should have an existensial crisis, because after all, what's he for?
And I don't want there to be a state of complete satisfaction. If there was a universal purpose, all our endevours could one day be achieved, and then what? Then we'd be at the anticlimax with nothing to live for after that.
Being human, I think, is about longing, and striving, jumping from one goal to the next. It's just the way we're wired. So I like to trick my mind by giving myself targets and goals and purposes. Another good tactic is to form friendships and help people out. I am trying to do what I would have done in paradise had it been true. But I have less time, so I am only doing what I really think is important and enjoyable.
That's what gets me through. Also some great YouTube channels like Alain De Botton's School of Life, introducing great thinkers in a relevant, understandable way:
https://m.youtube.com/watch?v=Ebt0X5ybm9Y
Or Crash Course Philosophy:
https://m.youtube.com/watch?v=mjQwedC1WzI
And other channels, like Kurzgesagt, which has this great video on addiction below:
https://m.youtube.com/watch?v=ao8L-0nSYzg
Maybe these will help.