I am tired to the bone ~ я устал как собака.
Bye the way, the short form adjective in this idiom is interchangeable. Ex: Я голоден как собака! - I am hungry as a dog!
Enjoy!
Уставать - v. - to become tired.
Kak - how, as, as(like), what, but, since.
Собака - n. Fem. - dog, hound.