It could be anything from teeth problems (malocclusion), to a hairball (trichobezoar) in the stomach, cecal stasis from a variety of bacterial over-growths (such as: Clostridium, E-Coli or pasteurella infection), or malnutrition. If the bruxism (teeth grinding) is only due to pain than it is possible that she has a urinary tract infection, or urolithiasis, or a upper respiratory infection.
As occurs in the cat prolonged anorexia can cause hepatic lipidosis (fatty liver disease), which can further debilitate your rabbit, raise liver enzymes and cause liver problems.
Therefore you must seek veterinary attention even if it is just to have your rabbits molars floated. This is not something that you can do at home. It requires sedation. Many vets charge less for small mammals. Also try calling the local humane society for affordable veterinary care.
the doctor gave u very good advice..u must seek veterinary care for ur pet......if ppl cannot afford medical care for their animals when they get them then perhaps they should not get the animal.Pet peeve of mine-my animal is sick and i can't afford to treat it!grrrr.!