Worried about the sky: the name of the Zhou Dynasty princes is in Qixian County, Henan Province today. There was a man in Qi who was afraid that the sky would fall. Metaphor is unnecessary or unfounded worry and anxiety.

Complaining about others: fate, fate; You: Resentment, blame. It refers to complaining and blaming others blindly when encountering setbacks or problems.

Much ado about nothing: asking for trouble. Nothing, just making trouble for yourself.

It means don't worry too much about things you don't have to worry about, don't complain, don't complain, and don't get yourself into trouble.