The Question and Answer section for The Fault in Our Stars is a great resource to ask questions, find answers, and discuss the novel.
All of them feel isolated from others. They have trouble dealing with their mortality and existing in the world of the "living".
Hazel started going to the support group because of her mother's encouragement. Her mother was concerned that she didn't want to leave the house..... to see anyone or go anywhere. She thought is would be good for her, and she was right.
Hazel really needs to go to Amsterdam. Everything is set up in Amsterdam and she needs to go.