on pins and needles

idiomatic

(idiomatic) Feeling sharp anticipation or anxiety; in a state of suspense.

Japanese Meaning

緊張や不安、期待と不安が入り混じって、そわそわした状態 / 先の結果を待つ間の神経が高ぶった状態 / 何かが起こることへの不安や期待で心がざわつく状態

She sat on pins and needles, waiting for the admission decision email.

彼女は入学許可の通知メールを待ちながら、やきもきして座っていた。

Sense（1）

(idiomatic) Feeling sharp anticipation or anxiety; in a state of suspense.

Merlin hesitated a moment or two, and I was on pins and needles during that little while.