Unraveling by Michelle Baldini and Lynn Biederman
The best (and simplest) way to describe this book is to say that it is Divine Secrets of the Ya-Ya Sisterhood by Rebecca Wells only better and for the younger set, something I think is really important with this type of dysfunctional mother/daughter relationship theme (in other words: a book for the daughter BEFORE she grows up and gets messed by the relationship she had with her mother).
The problems I have with Divine I do not find in this book, and the ending is considerably more clearly hopeful (though still leaves some to the imagination, which in this case is not the best ever). In short, you can walk away from this knowing that a a young girl's life is going to turn out much better because she had a chance to fix the relationship with her mother before growing up and going away.