Ask the vet - Cat
Can cats stop eating if they are depressed?
Vet at FirstVet answers:
Cats easily get stressed and affected by sudden changes in their environment. It is possible that a cat’s appetite may be affected if something changes in its home. However, it is not normal if it  :stops eating completely. If this is the case, there is an underlying disease process present. A cat that has lost its appetite for more than a couple of days should be examined by a veterinarian.