Eleanor Oliphant is Completely Fine by Gail Honeyman
Eleanor and Raymond form an unlikely pair as they save an elderly man who has fallen. Raymond, an awkward IT guy, and the socially inept Eleanor help each other to ease out of their individual isolation, allowing Eleanor to put together the pieces of her damaged past.
Review from School Library Journal:
Office worker Eleanor adheres to a strict routine that has insulated her from the memories of her traumatic childhood but has not shielded her from loneliness. But after she meets Raymond, she attempts to rediscover her memories and in the process learns how relationships (including those with friends, lovers, and colleagues) operate and that other people can be a source of joy rather than destruction. Readers may find Eleanor odd at first but will feel compassion and root for her as she grapples with severe depression and her painful childhood. Though the novel deals with dark themes, quirky Eleanor's firm bond with Raymond and their adventures lighten the tone. Teens will be spellbound as Eleanor unravels the mystery of her past and develops a sense of self.