Naomi Feinstein
The only daughter of parents whose lives have been very challenging. Her father is an immigrant and an orphan, and her mother struggles with mental health issues including serious depression. That means Naomi doesn't really have anyone she can open up with and talk to, and she falls in love with her first childhood friend, but when he leaves, she is desperate. At college, she makes friends and feels healthy, but when they succumb their own fates, she wonders what the meaning of friendship really was.
Teddy
Teddy is the love of Naomi's life, because both she and Teddy were extremely isolated, lonely people as children, raised to wonder whether they would ever find anyone to love. Then, they found each other and became instant besties. They even claimed to have fallen in love, as children. But their relationship ends abruptly when Teddy's parents take a new job and move away. They can't really keep in touch, and Naomi is alone again.
Naomi's father
We know Naomi's father fairly well from the story, but basically, he lived in another country as a young person, but he was forced to immigrate to America, and his parents died, so he is an immigrant and an orphan, which are burdens he has to bear daily. That means that Naomi can't get quite what she needs from her father, because there are real life memories that prevent him from seeing things her way.
Naomi's mother
Naomi's mother is also a representation of Naomi, because it is from Naomi's mother that Naomi learns about depression from such a young age. As a child, she felt sad for her mother, because she could tell her mother was in pain. Later in life, she finds that she has to push through her mother's depression before they can truly communicate—a heavy burden for an only child. She also learns from her mother that loneliness is crippling.
