Ok, so my dad's cat for the past week or two has lost her voice almost and she keeps hacking like she is going to throw up or has a hairball. She has been using the litter box and she has been eating canned food cause I don't think she has been eating the hard food. I am not sure if she has been drinking the water or not although it seems to go down so she might be. She is a short haired cat. I don't know if it can be something serious or not. Can anyone give me an idea of what the problem might be? Thank You.