This is difficult.
If this was a friend, you wouldn't go so far in trying to mend something that you never broke; but she is your daughter, and that changes everything in how you see the situation. Try to consider here that your Daughter is no longer your baby-girl; she is an adult and as such she is the only one who is responsible for her actions; in a situation like this, it seems that she doesn't think too much about what it is she does that affects you. This is the hardest part for you.
There is no easy road here for either of you. It will take time and understanding; more for your Daughter than for you. You will accept her minor indescretions, because that's what parents do ... but you can't be expected to open your door to find here there; carrying emotional baggage with her. It's a very hard emotional roller-coaster for you, I have no doubts she has issues too, but it's *you* who carries her load and is there to help her when she needs it.
My guess is that she doesn't see this clearly enough to *know* what she is doing to you and she sees you as somewhere to go when things start to go wrong in her life. Tough-love springs to mind, but I would think the best avenue to go down would be to ask her to go to counselling ... and go along with her. If she did this it would soon come to light *exactly* what she is doing to you ... and exactly what she is doing to herself.
I don't profess to have the answer, but it's clear that you both cannot carry on like this. I'd say look for some help that can sit between you guys and impartially 'say it as it is'.
Take care of you ... and I'm sorry for the 'Epistle'
uhm, i guess there's some reason that's why she's like that. There may be a deep reason why she's drinking, maybe a traumatic experience or a bitter feeling? Try to understand her and be patient. Time will come when all will be right due to God's grace. :)