Single Sundays: Every Other Day by Jennifer Lynn Barnes
Synopsis for Every Other Day (from Goodreads.com): Every other day, Kali D’Angelo is a normal sixteen-year-old girl. She goes to public high school. She argues with her father. She’s human. And then every day in between . . . she’s something else entirely. Though she still looks like herself, every twenty-four hours predatory instincts take over …