YA/fantasy: heroine has ghostly helper who is a garbage bag

[Miriam]

Ghostly garbage bag helper appears when heroine needs to be warned about imminent danger, such as if she has placed trust in a character who is plotting against her. Helper usually warns her by moaning, 'Noooooo, (heroine's name)', and then specifying what she should not do. Book includes vampires (this is not a spoiler).
I listened to this audiobook within the last 4 years.

[Kate]

Miriam ~~
You can "bump" your thread every month or so. This pushes your thread back to the top of the folder instead of languishing here on page 96 from two months ago where fewer eyes will see it. Get back in the game! Bump!
You can do this by typing a new comment at the end of the thread, or even by typing the word "bump."
Good luck!