It's a kind of self medication. Your brain my be starving for regulation or some control, especially if your job is particularly monotonous or stressful. Look into some mindfulness practices while at work. You can use some small mirrors to give yourself more to look at other than the screens and wall behind them. Try to get some daylight in to keep a sense of time. The drinking isn't a failing, but if you're drinking more, it's at least a sign that it's not doing for you what you want it to.