The 5th Wave

5^th Wave by Rick Yancey

Cassie has always had a crush on Ben, but he didn’t even know she was alive. When the Others invade Earth, shutting down power and releasing a deadly virus to kill off most of the Earth’s population, life changes for Cassie and Ben are put onto separate paths to survival. This science fiction novel begs to be made into a movie at some point. 
The story continues in Infinite Sea.