七上八下

qī shàng bā xià

on edge; heart in one’s mouth

Character by character

七qī
seven

上shàng
up

八bā
eight

下xià
down

等成绩的时候，我心里七上八下的。

Waiting for my results, I was a bundle of nerves.

Tone: neutral.

Almost always 心里七上八下, as in the 歇后语十五个吊桶打水——七上八下 (fifteen buckets in one well).

Learn it in context

This idiom and thousands more are in Learn Chinese with Bao, with audio, pinyin and drills that make them stick.