Nicole, I was put on prednisone for 5 days once, and gained 10 pounds even though I was nauseus and didn't eat much the whole time. It is important to do the decreased dosage in order to stop taking the drug. It can make you feel awful, but in the long run it does what it is supposed to do. Stopping the drug suddenly will only make you feel worse.
As I recall, the 10 lb weight gain, dropped off easily after stopping. So, you shouldn't be concerned with that, as it is not permanent.
Hope you feel better soon.