Hey chainsaw welcome!
I remember when I was seeing my 3rd or 4th psychologist I asked a similar question. I said "is it the bad things in my life leading me to drink? Or the drinking leading to all of the bad things?" She said that it was sort of like the chicken and the egg problem, but it would be impossible to get to deeper issues if I continued to put the alcohol on top of it. It took me 3-4 more years of missed/wasted opportunities, embarrassing blackouts, and a DUI before I was able to find a way out.
That way for me was avoiding the first drink, A.A, SR, and a hybrid of other things. But it's important to find a plan that will help you avoid that first drink. It's like you said that one can of beer is the kicker. I heard it put best at a meeting tonight. Someone was describing "moderate drinking as 1-3 beers and stopping." To which someone replied, "well that's just enough to make you mad now isn't?"
Welcome again!