Pancreatitis in dogs

I took my 7 year old chihuahua to the vet yesterday for the second time in a month with the same symptoms...constipation, dehydration and she was just not acting like herself. The first time, June 2nd, took x-rays, nothing in the intestines...whew...the vet said she was just constipated, gave her an enema and Reglan for vomiting...a few days later she's fine. So yesterday, July 2nd, I took her in again for the same thing...blood work this time, she's got pancreatitis. She's on an antiobiotic, Flagyl, and Reglen... She pants continually, has not had a BM for 2 days and won't drink water. She's eating a little bit of chicken broth a few times a day. The vet says wait a few days but it's hard to see her this way.
Has anyone else's pet had pancreatitis? What did you do to make your pet more comfortable?
Thanks for any help or suggestions.