If someone or something is off balance, that person or thing is in a position where they are likely to fall or be knocked down.

A gust of wind knocked/threw her off balance and she fell. 一阵狂风吹得她失去平衡后摔倒了。

confused or uncertain about what to do next

Many Republicans were thrown off balance by the Democrats' landslide at the polls. 民主党在民意测验中的压倒性胜利让许多共和党成员乱了阵脚。