Janus no Kagami

Ozawa Hiromi, a second-year high school student, lives with her strict grandmother Takako who deprives her of all freedoms. One day, Hiromi faints and wakens to a new personality named Yumi who is the opposite of Hiromi in all ways. Can Hiromi stop Yumi?
(Source: FujiTV)
~~ Adapted from the manga by Miyawaki Akiko.