I am very proud of you.
I do not know you that well, but it takes a great deal of courge and I for one would be right there beside you and holding your hand your heart what ever needed to be held, to help you make it through this weekend with out drinking..

You know you can provide soda for yourself.
Just tell your "girlfreidns" you are no longer drinking. You have to stay on the band wagon. Do not falter, it will be hard with them drinking, but if you have the strenght to make it throught his weekend, then you can go on with the rest of your life knowing someone is watching over you, and you are far better off not drinking..

Good luck,