You do well to take care of yourself. Here's a support website for dealing with borderlines. It's a difficult disorder to deal with, but it's possible. CoDA and the BPD website have been an invaluable resource for me.
Has she undergone therapy for her BPD? Dialectic behavioral therapy (DBT) gives people a good chance of recovering from the disorder. I wish both you and your daughter positive outcome through this difficult time.
((hugs))
Borderline Personality Disorder - Support group for families and relationship partners