An idiom for when you're completely drained

Estoy hecho polvo

es-TOY EH-cho POL-voh — I'm exhausted (literally: "I'm made of dust")

"Después de la mudanza, estoy hecho polvo."
After the move, I'm completely wiped out.

"Estar hecho/a" + noun is a whole pattern of idioms (estoy hecho un lío = I'm confused/a mess). Once you notice it, you'll start hearing it everywhere.

"This is exactly what I say after a full day of back-to-back lessons. Estoy hecha polvo, every time."— Graciela