Definition

Either completely exhausted and depleted of energy, or beaten up and physically battered. Either way, you're not in great shape—you're just the tired version instead of the bruised version.

Example Usage

After working a double shift, I'm absolutely done in and can barely keep my eyes open.

Source: Urban Dictionary (https://www.urbandictionary.com/define.php?term=Done%20in&defid=7130643)