Ryan L-
Did the vet run any tests on your dog, such as, fecal or blood tests? Is there anything in the yard or house that she could be getting to? Here is a link that was very helpful to me when I was having similar issues: http://www.dogaware.com/health/digestive.html
It turns out mine had giardia and coccidia. After several treatments to rid of the parasites, they were left with sensitive systems also. They do well on Victor and Whole Earth Farms brands. And yes, WEF is made by Merrick which was bought out by Purina. But, I will continue to feed it as long as my dogs continue to do well on it.
Good luck! Please write back and report on your progress.
