Perna: good suggestion.
I remember when I used to attend AA meetings, the basic text said that the best way for a person to judge if they have a problem with alcohol is to attempt to control their drinking. So if you repeatedly attempt to only drink a certain way, or at certain times, or in certain places, or certain amounts, and you more or less repeatedly are unable to stick to that, and it occurs in conjunction with something like aggression, then there's a chance you could have a problem with drinking.
What you decide to do about it is up to you. Not everyone has to be a full-blown alcoholic to decide that their life is better off without drinking. The fact that you were a heavy smoker for 4 years and then became a heavier drinker when you quit smoking is something that deserves to be looked at. Cigarette smoking is a much more complicated addiction than people give it credit for. After quitting drugs, after quitting drinking (for the last time), smoking was so much more difficult. It took me over a year after my last drink or drug to finally be able to kick smoking. With addictive behaviour, it can bounce from one thing to another. Addiction/dependency/use is the disease/habit/problem (however you look at it); whatever a person is compulsively doing (drinking, smoking, gambling, eating) is the symptom, not the root.
Some people, as I mentioned, decide they don't like how they feel when they drink, and cut it out even though they are not even addicted. Other people are very heavy drinkers, even problem drinkers, and reach a point where they can somehow manage to control their drinking. I have friends like that. I don't understand it, simply because I myself can't do it; thus far, I'm an all-or-nothing gal. But I have also learned that whatever works, works, and it's different for different people.
Try some stuff. Rational Recovery is one, and there are also things like SMART (Self Management and Recovery Training) which focuses more on brainstorming and problem-solving rather than the 12 step approach of admitting powerlessness, etc. If you haven't already, you may want to talk with a counsellor or therapist, especially one who has worked with people with substance abuse concerns before. They're pretty easy to come by. They don't necessarily have to specialize in addictions treatment.
Whatever you decide, I wish you and your girlfriend the best.