Why are you allowing her to hurt you? I think that is the question you may need to answer. I suspect that if you detach enough that she can only hurt you if YOU allow it.
In terms of being her friend - I may be over simplifing this...but how do you deal with your other friends? Do you listen when they call? Do you help them when they need help? Maybe just try and listen to her. Try and understand her - as hard as that may be.
On an aside - thanks for your post to me buddy - thanks!
God Bless, Eric
"The difficulties of Life are intended to make us BETTER,not bitter". "Fear is a prison, where you are the jailer. FREE YOURSELF!" "Life is usually all about how you handle Plan B." - Jack3Beans