"I bowed down to the ground" or "I lay on the ground." Ezekiel did not fall by accident. He went down to the ground to show that he respected and feared Yahweh. (See: [[rc://en/ta/man/translate/figs-idiom]] and [[rc://en/ta/man/translate/translate-symaction]])
The word "Alas" is an exclamation that expresses fear and sadness. Alternate translation: "Oh no, Lord Yahweh" or "Ah, Lord Yahweh" (See: [[rc://en/ta/man/translate/figs-exclamations]])