My cat feels warm, is lethargic, and won't drink. What should I do?

This is a classic presentation of a cat with an infection, but it appears to be non-specific right now, so there could be many possibilities. They usually do have a fever early in the infection and will feel bad. They also tend to avoid eating and drinking. Not drinking is more concerning than not eating, because they can quickly get dehydrated if not drinking enough water. In order to promote water intake, you can add water to his normal food and possibly add pedialyte to his water.

It's best if you can get Monkey to a vet within the next day or two. The fact that he is lethargic and not drinking could indicate a severe disease. The vet would be able to help narrow-down the cause of this and prescribe the necessary treatment to make him feel better and keep the infection from getting worse.

I hope this helps and Monkey feels better soon.