It's not uncommon for dogs with severe diarrhea to then firm up and not go for a day - but just for the record, I'm really kinda shocked your vet told you to feed *just* cooked protein to a dog under digestive stress - that pretty much guaranteed constipation to follow. I would feed canned/sliced (or fresh) mashed potatoes (with a bit of butter too), with very small amounts of protein until her digestion stabilizes. Then get her back on her balanced diet.
The real problem w/ feeding just cooked meat is that everything natural is being cooked out of that meat - all the meat's natural enzymes (to help digest it normally), many of its natural vits/minerals, the protein chain is being changed; and there is no balancing of the dog's calcium-phosphorous ratio. So, there is a lot going on to upset the doggy's system.
