Why is my cat meowing, not eating, peeing, and losing weight?

Unfortunately yes, weight loss and increased meowing can often be signs of illness in cats. You don't say how old your cat is, but if she is middle-aged or older the first thing I would be concerned about is possible thyroid disease - hyperthyroidism very commonly causes both of these symptoms. It also often causes increased appetite, and sometimes soft stool. Other possible causes could be diabetes, kidney disease, or even a digestive problem like inflammatory bowel disease. I would recommend having Ittybitty examined by a vet - he/she can do a simple blood panel to check for most of these problems, and advise you on treatment options based on the results.

These sudden changes in temperament and the weight loss are commonly due to an endocrine problem called hyperthyroidism. The thyroid starts working more than normal increasing the metabolism (that is the cause of the weight loss) and causing behavioural changes similar to what you described. A clinical examination at your local veterinarian is essential to confirm this clinical suspicion and treat appropriately. A blood test and urine analysis are needed. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

I would have Zarry checked out by a vet as soon as possible. There are two conditions that come to mind that can cause a cat to lose weight despite having a good appetite: hyperthyroidism and diabetes. A vet will examine Zarry and discuss his medical history, and will probably recommend bloodwork to look for a diagnosis.

This is very concerning and may not related to progressing kidney, thyroid disease or diabetes. An urgent vet check and urine and blood tests is recommended. Do not delay investigation as early treatment is required

Please get him seen by your vet as soon as possible, behavior changes and weight loss in an older cat are always a concern. I would recommend blood and urine tests to rule out a uti, kidney issues or a hormonal condition such as diabetes or thyroid disease

While loss/grief can certainly cause behavioral changes in cats, losing weight, not eating and urinating everywhere make me worry there is an underlying health condition such as a urinary infection that is causing him distress. Not being neutered can also lead to marking behavior/stress if there is a female in heat nearby. It is a good idea to have a thorough exam done along with bloodwork, X-rays and urine tests potentially to determine if there is any health issue. If he checks out healthy, spending more time together may help him to relax some, as well as using a pheromone diffuser such as Feliway to help with the marking behavior/stress. If you think he'd benefit from a friend, gradually introducing a new cat may help as well, but can also be stressful.

With the symptoms you are describing I tend to test for advanced kidney disease or hyperthyroidism. I would encourage him to eat as best you can and get him to a veterinarian. With blood work and a urinalysis they should be able to give you a diagnosis and help direct you as to what is next