Well, the story line seems fine but there are some parts that get sort of choppy like:
"but at least Nick was proving himself as a worthy replacement.

Lauren ran over to Sarah, tears filling her big brown eyes. Immediately Sarah stood and hugged her friend."

Also, it'll be better if you placed more emotion to her actions (example: I ran. More emotion: I ran stealthily for fear of being caught...etc.) and more "drama" when she wakes up like discussing her fear or maybe even crying cause it doesn't seem realistic that she's so calm (i would bawl my eyes out if that happened to me).

I know that the ending is supposed to be dangling, but i think it's too dangling; you can build your plot more (it's a very good plot so far).

:D