Hi coressat, I am sorry to hear you are grieving from the situation with your girlfriend.

The most difficult post for me to answer is one about a girlfriend or family member of the member at Psych Central. There is the unknown of what triggered their reaction. Is it a setback in their condition or something else? Do you know her family members well enough to call them up and compare notes about what kind of communication they are getting? Or a mutual friend?

Also take care of yourself. It must be traumatic for you. Some people even get a therapist to help talk things out just to heal yourself.

Here are some articles at Psych Central on how to help a friend.
Psych Central - Search results for Helping a friend in depression

Remember to take care of your own self too.