For an alcoholic of my type, "just don't drink" doesn't cut it. If you can stay sober on that sort of thinking, you are not like me. I tried it a thousand times. It was the first thing I thought of. I lacked the Power to pull it off.
What you are talking about is emphasised over and over in the Big Book of Alcoholics Anonymous.
"Page 43, Once more: The alcoholic at certain times has no effective mental defense against the first drink. Except in a few rare cases, neither he nor any other human being can provide such a defense. His defense must come from a Higher Power".
As Grungehead said, in hindsight we can often see what went wrong, the chain of events, but IME, we almost never see it coming.
The cause is the obsession of the mind. The idea comes back that it is ok to drink, and all the good reasons for not drinking fade away into the background. They do not come with sufficient force to save us. In my case, they never came at all. It is that insidious insanity of the fatal first drink. It is like a state of psychosis, the reality of the situation completely escapes us.
I made decisions galore to quit. I meant it with all my being. Sometimes I would be drinking days later, sometimes only hours. Most times I don't even remember taking the first few. I remember often taking the third and then remembering I was not supposed to be drinking.
What you have been experiencing is very normal for the real alcoholic.
"page 24" The fact is that most alcoholics, for reasons yet obscure, have lost the power of choice in drink. Our so-called will power becomes practically nonexistent. We are unable, at certain times, to bring into our consciousness with sufficient force the memory of the suffering and humiliation of even a week or a month ago. We are without defense against the first drink."
This was my experience, and the experience of hundreds of others I have met. It sounds a lot like your experience too.