Ok....Some round numbers. 2500 calories every weekend. Let's say 150 calories per beer. That's almost 17 beers per weekend. I went to one of the all time great binge drinking schools, but that seems excessive to me.
Instead of quitting drinking for 3 weekends, try cutting it in half permanently. You'll lose your 3 lbs in 6 weeks instead of 3 weeks and you won't just gain it back.
Besides, I think you might find other areas of your life enhanced by cutting back on the drinking.
I'm guessing that you will have a very difficult time cutting back. If you can't get by on 4 drinks a night on weekends, it's time to quit permanently. Seek help. Seriously.