My cat became less active, doesn’t run, just lies and sleeps; urine sticks to fur; but normal appetite, stool, no sneezing

If a cat suddenly becomes inactive but its spirit, eating, and stool are normal, consider: 1) it may be in heat, becoming dull and listless; 2) feeling cold in winter, when cats are less active and more sleepy, which is normal; 3) psychological stress from a new environment or stranger, causing mild depression and sleepiness.

You can observe at home for one to two days. If the inactivity comes with vomiting, diarrhea, poor appetite, or other pathological signs, take the cat to a vet.