Yes. Quit drinking.
Then address the spiritual and existential problems but that is a life time story. AA really works. My sister that is not an alcoholic practices mindfulness. Just saying that there are books and videos, some are free and some not.
Existentialism per se was originally a movement of Camus and such, that watched himself from the distance. People have always added the question "why are we here"?
I am glad we are here!