my vet used to have lilo drink a little plain pedialyte to help her stay hydrated when she used to vomit or had diarrhea. a little pumpkin should be fine but it probably is just the change in food thats causing it all. if she's not better in a a day or two and you see any dramatic changes in her energy level it is vet time .
id just call the vet to let them know whats happening and ask for advice just in case. i hope she feels better soon!
How to Stop Diarrhea in Dogs