Well, if we're talking medieval England, tea wasn't around yet.
It didn't come until around the 17th century, I believe. It was originally from China, but the British Empire introduced it to India and mainly got it from there. So the quintessential English drink isn't even English. I always thought that was amusing. Alcoholic beverages like ale and beer would have been the main drink. The fermentation process made it safer to drink than most water at the time.
As I understand it, only royalty was really allowed to hunt and eat game animals. Mutton, beef, and chicken would have been okay, though. Mainly, they would have eaten a lot of fish. In Mike Loades' documentary
Going Medieval, he shows a big ol' pike - the fish, not the weapon - being wrapped in a pastry crust and baked. The crust acts like medieval aluminum foil. It actually looked rather tasty. He also showed this curdled cheese/egg mixture stuff which did not look tasty at all.
Then there's pottage. The idea behind pottage is to basically take any scraps of edible substance you had at hand and boil the heck out of it.