Mystery survival novel about kidnapping

I don't remember the title or the author but I read it in 5th grade so around 2010 or 2011 maybe? It's about a girl whose mom's boyfriend kidnaps her out of jealousy because he wants her mom all to himself. I think he mimics recent kidnappings done by someone else in the book when he takes her if I remember right. He leaves her in a cabin in the woods, my guess is to die, but she escapes the cabin and based on what she was taught, I think by her grandfather, she survives in the woods on vegetation and maybe insects too but mostly remember her deducing which tree had bark safe to eat and her making strips and boiling it then eating it like pasta.

In the end, her mom says how can she trust her judgment anymore.

In the beginning, before he took her, he and the mother were washing the car and he sprayed her t-shirt then (as written in the book) ogled her boobs. It was remarked how annoying it was that they act like teenagers or something.

I also remember that he knocked her out by injecting her with something. She felt like she was being followed and then that happened. I don't remember if it was related to the kidnappings he was copying or if he just didn't want her to struggle but yeah lol