know if one is coming or going
To feel able to think clearly; know what to do. — Usually used in the negative or with limiters.
On Monday, the car broke down; on Tuesday, Mother broke her arm; on Wednesday, the children all became ill with the mumps; by Thursday, poor Father didn't know if he was coming or going.
My cousin is so much in love that she scarcely knows whether she's coming or going.
Compare: IN A FOG.
Source: A Dictionary of American Idioms