More than one can handle with 荷が重い
力量にくらべて、負担や責任が大き過ぎる。
The burden and responsibility are too great compared to the degree of ability to get things done.
Goo Dictionary
The expression 荷が重い literally translates to “the load is heavy”. It is used metaphorically to express the feeling that a responsibility, task, or situation is too much to handle, overwhelming, or burdensome.
A similar idiom in English is to “have too much on one’s plate”.
