Falling Awake.

Jordyn Merrill, a fifteen-year-old girl with five younger sisters, is still recovering from her mother's tragic death, and being forced into the responsibility of looking after all her sisters. On the two year anniversary of her mom's death, Jory is involved in another car crash, then she wakes up assuming that it was a nightmare until she finds that her entire family except for her bratty 13-year-old sister, Cassie, is gone. The two of them, and another boy they find try and figure out what the heck is going on while their health deteriorates and they experience strange dreams. There are almost constant fights between Jordyn and Cassie.