If you really want to protect yourself fully against drinking again, it's worth spending a bit of time working out what the function of alcohol was - why were you drinking?
I'm not suggesting that you've necessarily got a huge unresolved trauma, but it's likely that you were using alcohol to try to solve a problem. And as a solution, it failed - as it always does.
It might be a straightforward answer: it might be that you drank to gain confidence, and that drinking then went on to provide you with some comfort and security. These gains will only have been short term, and the negative consequences of alcohol will probably have actually made you less confident, less comfortable and less secure.
It might also be that simply by not drinking for a while, these matters will, without much thought, resolve themselves. Some drinkers just find themselves in unhappy circumstances, and have used alcohol to obliterate their ennui or their misery. In these instances, there are obvious clues about what to do. You'd need to find alternative ways of feeling OK about yourself, of relating to other people, and of soothing yourself. Or you'd need to alter whatever it is in your life that you're fed up with, rather than just masking your unhappiness.
This section is only scratching the surface. It might be that you can work a lot of this stuff out on your own; equally you may have been doing some deft and nifty footwork by using alcohol to avoid things that you find uncomfortable or difficult, in which case I'd recommend finding a skilled and experienced professional to help you untangle it all. Again, if this is going on while you're drinking, then concentrate on finding someone who can help you to stop. Once you've stopped for a while, you might want to move on to a non-alcohol specialist counsellor or psychotherapist.
And finally, don't get too hung up if you can't find a reason why you were drinking. Concentrate instead on the present, and your reasons to not drink.