I'm sorry to hear that your friendship is strained...and possibly ending. Have you talked with her about your concerns? Maybe she is unaware that she is pulling away?
I have gone through the same thing with an old friend of 20 years.
What I have learned is that relationships have a "life-death-life" nature, or cycle about them (when I say "death" I do not mean in the literal sense, more of the emotional sense). Today our friendship is at a different level, more supportive than ever before, and much healthier communication. The tough times were tough, but the past few years have been good. Of course it is nothing like it used to be...we talk weekly now rather than daily
I read a fantastic short story that explained "life-death-life" nature of relationships (Women Who Run with Wolves...forget the author at this time...sorry), and I have found it to be true.
It seems as people grow and mature, they need to break old ties in order to feel they have the space to grow. Once they have experienced the change that they seem to need in their life, a door will open to rekindle the relationship.
(Hmmm...just a thought...it sounds as if you were the giver in the relationship and she was the needy one??? Maybe she does not need anything??? Hmmm...just a thought...)
You sound like a great supportive, and loyal friend. I am sure that when she is out in the world she will eventually miss your friendship, need some advice or just a tender ear to listen...she will contact you.
Good luck...