You need to take your Cat to a Veterinarian ASAP. You say you are not poor, whatever that means, but if you love your pets so much how on earth can you let them suffer as your cat is obviously doing. As for being in pain? How on earth do you know this? Animals simply do NOT react to pain as people do and one of the first signs of pain in an animal is a lack of appetite.
Do something for your Cat or else take it to a shelter where perhaps they will help.
Thank you. I will consider