at sixes and sevens; perturbed state of mind; in a mess
七 · 2 strokes
Depicts two lines crossing. Based on the original meaning "cut", now written as 切. The current meaning is a phonetic loan.
上 · 3 strokes
Originally a small line or dot above a longer line, indicating "up". The vertical line was added to distinguish the character from 二 (two). Opposite of 下.
八 · 2 strokes
Pictograph of two lines facing away from each other. The current meaning "eight" is a phonetic loan. The original meaning "separate" is now written as 別.
下 · 3 strokes
Originally a small line or dot below a longer line, indicating "down". The vertical line was added to distinguish the character from 二 (two). Opposite of 上.
考试前他心里七上八下的。
Before the exam, his heart was pounding with anxiety.