If you think your drinking is a problem then it really is and you need help.
If you drink on the weekends or at parties then I do not think it is a problem as long as you do not have a party every night.
If your GF does not drink and you do this can create a big problem in your relationship. Alcohol is not a cure nor an answer. If you can go without and be happy then do it.
I would sit your GF down and have a talk with her to discuss your drinking and the effects it has on you versus other people.
