Teen novels about sleep people?

I read a book a few years back about a sandman, and it was about his contract being up, so he was transitioning back into a human. During his time as a sandman, he had a list of people he put to sleep every night, and one was a girl who was kidnapped. His kindness was putting her to sleep so she didn't suffer during that event.

Cut to the present, shes dating a jock, who drives home sleep deprived, and he dies. He becomes a sleep man, and it's ok with being dead. As the sand man whos becoming human again gets closer to the girl, her dead ex is getting annoyed, so at the end of the novel the ex tries to kill her. The new guy jumps in front o the car and wakes her up by being hit, and the book ends with her and the now human guy, dating.

Anyone know what this book was called?