It is important you go to a vet to work out what is wrong.
When a cat who usually has a great appetite stops eating, something is very wrong. Particularly so when this is a young cat. This may be something that can be treated but it will probably not get better on its own.
Inappetence often indicates nausea in cats, even if you are not seeing vomiting. A fever of 105 F is very abnormal - your cat needs a thorough medical workup, probably including some blood and imaging tests, to work out what is wrong. There are any number of reasons why your cat may not be eating, and this cannot usually be solved without any tests. Please take your cat to a vet as soon as you can.
In the meantime, offer a selection of diets. Warm up the wet food to stimulate appetite (the stronger you can make it smell, the better).