Center of Gravity by Shaunta Grimes
Tessa has always been anxious, but it's become worse since her mother died a few months ago. To calm herself down she cuts out photos of missing kids—from milk cartons—and keeps them in a file. It helps her feel like she's not alone. Her friends are drifting away. Then worst of all, Tessa's dad announces suddenly that he's getting married—and that his fiancé is pregnant. His fiancé's parents gift them a house at the beach, and Tessa must move. As Tessa navigates new friendships with a group of misfit boys and a new stepmother, she realizes she must let go of old friends and old habits if she wants to regain control of her life. Once again, Shaunta Grimes delivers a character and story that will speak to many readers.