I have a 3 year old cat that had sudden weight loss, she has been this weigh for 2 months now. I took her to the vet in the beginning and he did x rays blood test and they all came back with nothing. Her is what is wrong, She has lost a lot of weight, almost bones now. She isnt as energetic bud loves to play with cat wands She eats and drinks and goes to the bathroom fine No vomiting of any kind What should I do and what could the problem be?