Thanks for all the replies so far, very good insight.
For me, the first time the problem really overwhelmed me was when I started the last year in my undergraduate studies. Three weeks into the autumn semester I was so strung up, that if I missed another seminar, I'd fail the course and wouldn't be able to graduate that year. Given that being absent twice was allowed, so that's what the case was on the third week. Took an academic leave for a year, to regroup and heal - but what did I do actually? Pretty much kept going at the same pace, until the 12 months were over and I was to return to get my degree. Three weeks in - I was at the exact same position than a year earlier. For a moment there, I had had it. Got professional help and stayed sober for 9 months, until I graduated. By that time, the boredom of 'not drinking' and constantly not solving problems I'd created while drunk had built up my confidence to the point where three beers really didn't seem like they'd take me down the same path again. Well, they did.
The problem was back then as it is now, that I somehow cannot come to grips with the finality of the thought. For some inexplicable (inexplicable to me, that is) reason this has stopped me from leaving the bottle behind for good. That's why I wanted to ask about other's experience.
All the 'I'm still young' elements play a part in this indecisiveness.