Yep, she sounds like a classic BPD! Have you checked out bpdcentral message board? You might find it very helpful. I know it sometimes feels like you're going crazy yourself because they are SO egocentric, but yet intelligent and high-functioning. But LORDY they cannot have healthy relationships if their lives depended on it! My daughter has had several months of residential treatment and is doing well, but for a long while it felt like I was suffering from PTSD. Maybe that accounts for your "empty" feeling?