Whats wrong with my dog?

Okay so I found out my dog was in the hospital, and she spent the night there. The doctors said she ate some tree bark and leaves and thats not un usual for dogs to eat that. But the reason why is because her rear and legs were trembling and she couldent walk. The doctors did tests and they said everything was normal. Blood, urine, feces, all that. But they also said it could be neurological. And right now shes kinda lazy. Shes laying down resting next to me. I think she shaking is a little bit there but when I walked in the door she seemed pretty happy. Oh and shes 9 years old. What does this mean? Is she going to be okay? Will she die? Please help! thankss :)