If you are at a loss you may wish to try alternative medicine, I have personally seen this work with many animals. You should contact a local Naturopath, Homeopath, or Herbalist in your area and they should be able to advise you of someone qualified in your area.

Remember to make sure that they are QUALIFIED because in some countries (don't know about the US) you don't need qualifications to claim your status!

Good luck and I hope something can help little Missy.