My Cat Has Not Been Eating Or Drinking Anything For The Last Two Weeks. The Vet Gave Her Fluids Put On Antibiotics. She Is About 15 Years Old. She Is Very Feeble Now.Do Cats Have Old Age Sickness?

You are right. There are many complications which can be attributed to old ages in the cats. A one year old cat is equal to 16 years of age in human an according to this formula, your cat with 15 years of age will be equal to 73 years. There are many possibilities of not eating and drinking in your aged cat like

1. Immune system become weak and more prone to develop infections
2. Reduced blood circulations
3. Loss of memory
4. Loss of vision
5. Diseases of gums and teeth which causes loss of appetite.
6. In old cats, there is decrease in smelling sense so result is loss of appetite
7. Kidney failure, hypertension, arthritis, hyperthyroidism, diabetes, IBS and cancer are common.

So, let the vet do their job to improve the quality of life of you cat.

Your cat may have a combination of several things that are contributing to her desire to not wanting to eat or drink. Let your vet continue with their treatment to the best of their ability. The most difficult part of the process is that you dear cat is not able to talk to you or the vet to tell you what hurts. Be patient and persistent.