Hey Brainsy,
your initial post described what used to happen to me. I had to repeat it a few hundred times before I was able to see what was happening, and I only got to see that with some outside help. My pattern was to decide not to drink and then end up taking the fatal first drink without any reason and often with no thought of the consequences. Having taken it and put alcohol in my system, an overpowering craving meant that I would continue to drink way past the intended amount. It takes about 5 days for the alcohol to be gone from my system, so I tended to continue on a binge, driven by the craving until I became too sick or broke to carry on. Then would come the hangover and withdrawal, then the craving would be gone, and a dry period would ensue until inevitably I would take the fatal first drink and set it all in motion again.
The answer for me has been to find a way to combat the insane thinking that puts the fatal first drink in my hand. While I used to think it was due to a number of external factors, I came to realize that the main problem was my alcoholic mind.