Something wrong with my Suki

I rescued my sweet cat Suki while living in Hawaii many years ago when she was a kitten. She is 16 yrs old and has been with me thru everything. Never leaving my side. She is a indoor cat, since I now live in Las Vegas and it would be cruel to leave her out. She is litter trained but she actually uses the doggy door and does her business outside. She is spayed and has been healthy up til a few days ago. She has been falling over to her left. Losing balance and sleeping a lot. She still has a big appetite and drinks plenty of water. I have come to this forum because I have exhausted all other possibilities. I am unable to take her to a vet as I can barely afford medicine for my lupus. I'm afraid I may have to have her euthanized. Before I do I need to know if there is anything I can do.

This is Suki, she has always had her tongue out, lol, since a kitten.

@kaleenka Hi and welcome to TCS although I'm sorry for the circumstance.

What you describe sounds serious, we can't diagnose from here, but just because it sounds serious doesn't mean its expensive to treat. I hear what you say about vet costs, but even euthanasia costs money so before you spent money doing that, I would at least have an exam done by a vet.

Also see this thread if you feel you cant afford a vet.  http://www.thecatsite.com/t/155462/cant-afford-a-vet-please-read