I am so sorry. If I were you, I would be so hurt... in fact, I did have a similar experience with my childhood friend and that friendship ended five years ago however I am still grieving that loss.
I don’t know your friend, or her communication style, her approach to handling conflict or her ability to sharing her emotions.
With that being said, if I were you, I would not contact her anymore. I am in complete agreement with Bill.
She either does not have anything positive to say or she is giving you the silent treatment or she is incapable of handling conflict.
I agree with your therapist; meaning if she has a reason for not communicating with you anymore, she should kindly come forward and share her feelings and issues. A friend shouldn’t let someone wait and worry, especially if that someone has been a close friend and has an illness.