There's something to be said for the lowering of inhibitions and a bit of relaxation on your instrument. Some of my best ideas have come out of being incoherant, but additionally I have vomited while playing and made a total mess of things. You can't have it both ways. Have fun and make an occasion of it with your mates. But if you have to open a bottle just about everytime you want to jam, practice or gig I'd suggest a visit to the doctor.
Alcoholism is an illness.
But from what you've outlined, I don't think you have anything to worry about. I do practice after I come in from my local pub on Friday. Plus has anyone played well when totally bollocked, even though they did not intend to get that way. There's something to be said for the lowering of inhibitions and a bit of relaxation on your instrument. Some of my best ideas have come out of being incoherant, but additionally I have vomited while playing and made a total mess of things.