know if one is coming or going

know if one is coming or going or know whether one is coming or going  {v. phr.}

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.