Is she seeing a psychiatrist?
Is she seeing a therapist?
These two things can *help* the problem but she has to want to get help. However, there are things YOU can do to reclaim your life.

These came off the top of my head:

1. Set boundaries.
This is probably the hardest thing that you will have to do, but it's necessary for your sanity. As my boyfriend has shown me, tough love is sometimes the best form of it. These boundaries can include telling her that she can only call you during certain parts of the day, so you're not constantly worrying about the next phone call. Putting her through some kind of therapy so she can learn to be more mindful of others. Telling her she needs to at least make an attempt to try medication if it had helped at one point. If you don't set those boundaries, she is going to continue to consume you.
2. Outline what behaviors are appropriate.
You can SUPPORT her, but you cannot be her therapist. Therapy and support are different. She is old enough that she could probably fill out paperwork to get some state insurance and maybe even disability pay if it is severe enough. This could help her learn some more independence.
3. Give yourself a break.
You are a full time parent and have other children to attend too. As my boyfriend said, the average person lives 79 years in this day and age. You're only half way there and you want to enjoy your life. Yeah, this can be debilitating but bipolar is a disease and she needs to realize that it can be managed successfully. By allowing her to constantly call you, you're enabling the behavior.

(((helpmecope)))