Be at your wits’ end
Definition 1 of 1
Pro Tip 1/3Emotion Intensity
The phrase expresses strong frustration or anxiety when no options seem to work. 
She was at her wits' end trying to control the rowdy classroom.
Pro Tip 2/3Personal Limits
It suggests a person has reached the limit of their ability or patience. 
Lost in the city, I was at my wits' end looking for the hotel.
Pro Tip 3/3Figurative Use
This is a figurative expression, meaning it should not be taken literally. 
The puzzle had him at his wits' end; it was really complicated.