You have a drinking problem. You know alcohol aggravates your depression but you drink it anyway. Given your denial of this and young age I'd imagine you've never sort medical treatment for your depression or mood instability.
You like to binge on the weekend and your workplace is pro alcohol so with your problem you're in serious danger of becoming alcoholic if you haven't already.
I hope you can just stop as you plan too - alcoholics like to make promises like that to themselves but they don't last long. If you fail be honest with yourself and accept you drunk knowing the harm it does as you couldn't not. Alcoholics have a habit of deluding themselves into believing they only drunk because they chose to for whatever reason.