Thanks for the advice guys. I will try your suggestions. Yes, she's the only cat in the house just me and her. I've never change her litter formulation for a year now. I will try to get her a new litter box. I don't think she has UTI. Actually she's using the bath tub as her permanent litter box now she don't do it anywhere in the house anymore. Do you guys think it's a good idea just to put her litter box in the tub? I clean the tub everyday with bleach.
Another thing I remember last winter she has fleas I don't know where she got it because she never go outside and she was not really herself. She started staying in one place sitting on the window sill only come down to eat she lost lots of hair and weight. That's when it started. The vet gave her advantage and a week or so after the fleas are all gone. That's when she started being happy and frisky again and gaining more weight. BUT the pooing and peeing in the tub never change..