What is the main conflict in Memoirs of a Teenage Amnesiac by Gabrielle Zevin?

Memories of a Teenage Amnesiac is a novel by the author of Elsewhere, Gabrielle Zevin. The story follows the main character, Naomi Porter, as she tries to put the pieces of her life back together after suffering from amnesia. When Naomi falls and bumps her head on the stairs of her high school, she wakes up without the memories of the past four years of her life. The doctors cannot find a medical reason for the loss of memory. Some of the doctors as well as Naomi and her physics teacher, believe she might be blocking out a traumatic experience that occurred during the four-year period. The story slowly reveals how Naomi has her pick of traumatic events to choose from.