Welcome to JustAnswer! I am a licensed veterinarian and would be glad to help!
When did this start?
Did you see vomiting?
no none of that his cat box is clean. he was fine yesterday.
If you feel the belly, towards the back where the bladder is - is that area hard or painful?
With what you write - his signs are compatible with SERIOUS illness.
I can not rule out a urinary blockage here:
It may be other serious illness as well.
This really would be something serious enough to have an evaluation as soon as possible.
You can try to offer small amounts of pedialyte for hydration and electrolytes. You can even purchase a dropper from your local pharmacy to offer the water/pedialyte mixture by mouth.- A calorie dense nutritional supplement such as nutrical (LINK HERE)- Another option would be baby food. If you are going to try this, please purchase baby food that does not have any ingredients such as garlic or onion.Many baby foods now will only have the ingredients of the item and water...for example chicken and water. But they will not have any other salts or seasonings. This is what you need. Just chicken and water or beef and water for example.
You can also rub some karo syrup or pancake syrup on the gums for blood sugar help!
_____________________________________________________________________Please click "ACCEPT" if the information I have provided has been of help so I receive credit for my work. Bonuses are always welcome and appreciated. Thank you.The above is given for information only. Although I am a licensed veterinarian, I cannot legally prescribe medicines or diagnose your pet's condition without performing a physical exam. If you have concerns about your pet I would highly advise contacting your regular veterinarian.