My experience was that the alcohol caused the depression.
I don't have any close friends and my family has all died. I'm also your age and not working. I found that being alone is not debilitating once I quit drinking. I am entirely capable of finding people to spend time with when I feel the need. The alcohol really did a number on my sanity and ability to have hope and joy.
I think you'll like AA meetings - at the very least they got me out of my own head, got me dressed and out of the house, and around people who understood and were working on their issues.