Alcohol, Welbutrin, and weaning

I am not an alcoholic, but I admit I like to drink, especially on weekends.  Because I am on Welbutrin (150 mg XL per day) this causes me to be depressed, severely, for the first couple days of the week (Mon, Tues).  I've been taking this medication for years and would like to try weaning myself off so that I can manage life without antidepressants, and also avoid the side effect of depression every time I drink.  What is the best way to wean myself off, and do you think it is better for a drinker with depression to be off the meds or on them, if they've no intentions of quitting drinking?