Becoming lightheaded with 気が遠くなる

The expression 気(き)が遠(とお)くなる literally means “one’s spirit feels distant” or “the mind feels far away”. It is often used to describe feelings of extreme overwhelm, fatigue, or astonishment. Your 気 (spirit) does the action of 遠くなる (to become distant) from you. It can also mean to faint or pass out.

Dictionary Definition

意識(いしき)がなくなる。正気(しょうき)を失(うしな)う。

To lose consciousness. To lose one's sanity.

Goo Dictionary

Examples

Dazed by a wristwatch with 気が遠くなる

At the stroke of midnight, Chibiusa wakes to a mysterious glow from her new wristwatch. She gets out of bed in a daze, and begins to leave the room. Her cat, Diana, bites her on the arm, returning Chibiusa from her trance.

ちびうさ:

「この腕時計(うでとけい)見(み)てたら気(き)が遠(とお)くなったのよ〰〰」

“When I looked at this wristwatch, I became lightheaded〰”