it sounds like you've gone very low carb? you are likely in ketosis and suffering a bout of carb flu. your electrolytes are out of whack. have some avocado, that cantaloupe, and drink some miso soup. drink LOTS of water. take it easy too.
As I ate the oysters with their strong taste of the sea and their faint metallic taste that the cold white wine washed away, leaving only the sea taste and the succulent texture, and as I drank their cold liquid from each shell and washed it down with the crisp taste of the wine, I lost the empty feeling and began to be happy and to make plans.
– Ernest Hemingway