I have a problem with my 18 yr old kitty.?

Too much protein will cause kidney failure. My husband just lost his 16 year old girl a few months ago and the vet said as they age,the liver can't break down the meats with high protein. We got special food from the vet for her,but she was wobbly like yours too. I'm sorry,you need to see your vet asap,best of luck.