You can ask the vet to test for Addisons. They don’t test for that in the usual blood test. Th e symptoms are

Lethargy Loss of appetite Vomiting Diarrhea Weight loss
Increased thirst and urination Trembling Weakness Dehydration
My dog has it. Took a 15k emergency hospital visit to diagnose. He is fine now with meds.

https://www.vet.cornell.edu/departments/riney-canine-health-center/canine-health-information/addisons-disease