Andrews, V. C. (Virginia C.). Mirror sisters series.

"From the New York Times bestselling author of the Flowers in the Attic and My Sweet Audrina series, now Lifetime movies, comes book two of the haunting saga of identical twin sisters tortured by their perfectionist mother--until one of them snaps. Haylee and Kaylee Fitzgerald are twin sisters who have been forced to be identical in every way by their domineering mother. She insists they wear the same clothes, eat the same food, get the same grades, and have all the same friends. But both are growing weary of her obsession with their similarities, so when they finally attend high school, they find little ways to highlight their independence. The transition isn't as easy as expected, however, and soon both sisters are thrust into a world that their mother never prepared them for--a world with far more dangerous consequences than just upsetting Mother"--