Hi Shayma,
It certainly sounds like something has changed with your cat. A few things that come to mind would be kidney disease, diabetes, or an infection. Unfortunately, an examination is needed and probably some blood tests too. I would encourage you to talk with your veterinarian and see what an exam costs to start. There are often third-party payment plans you can apply for or check with family and friends if they can help you get your cat looked over.
I wish you the best of luck.
Dr. Ryan Llera