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.