Have you checked for tick-borne illness? I almost lost Lynn-Dah last year to a complex of Erlichia, Anaplasmosis, and a form of Lymes Disease that caused her to love nearly a fifth of her body weight.
A blood test will show.
We don’t have trouble with ticks here. The Vet did a full blood test on him and said everything was good except for a high white blood Cell count - indicating an infection ‘somewhere’. He did a urine test and didn’t have a bladder infection.
He gave him a high powered antibiotic shot and meds for nausea and diarrhea. Plus he gave him one of those one day flea pills as he had fleas. The once a month flea/heartworm drops I’ve been putting on him don’t seem as effective as they used to be. The worst thing is that he wasn’t eating and he’s an eager eater, lol.
Poor baby, he really got ‘dosed’ up!!
I remember when Lynn-Dah was sick, it’s always frightening.