Hello
TXMichWelcome to the group. I am sorry to hear about your daughter. You are probably right that this is just the beginning. The good news is she has a supportive person in her life namely you! I know what you mean about being loved one minute and despised the next. That is very typical behavior for someone with BPD
It is called splitting. They are not able to see people as having an independent existence outside their immediate experience. Psychologists call it lack of object constancy. If they feel good when you are around you must be all good. If they feel bad when you are around you must be all bad. It is hard for the nonBPD in a relationship to cope with but there are communication skills that help. Perhaps a good place to start would be validation. Here is a great article that explains what that means.
Don't Be Invalidating You don't need to agree with your daughter's ever changing perceptions of you in order to affirm the intense feelings that are behind those perceptions. I have found the practice of validation helps my relationship with my BPD son. Maybe it will help you with your relationship with your daughter too.
Hugs
Faith