Question

I have a 2 year old cat that was extremely overweight. She is extremely furry so I didn't notice how much weight she had lost. Two nights ago, she was acting so strange and wouldn't move from a corner in our basement that I went to pet her and was shocked that I could feel her spine poking up under her fur. I felt her sides and can feel her ribs. I picked her up and she has lost at least half her weight. She has also been urinating on the carpet instead of in her liter box which she has never done before. Her urine is dark gold. She wouldn't eat her dry cat food so I gave her some tuna fish two nights ago when I saw how thin she is. She gobbled it down but the next morning she had vomited it up. She wouldn't eat anything yesterday but this morning she ate a little more tuna. I recently spent $2,000 on a little Yorkie that almost died when we bought her. I am out of funds for vet bills. Any suggestions???