at the end of (one's) tether

Completely worn out, exasperated, or exhausted; having no more patience, endurance, or energy left. Joshua has been throwing a tantrum all afternoon, and with all the other things I have to get done, I'm simply at the end of my tether! Daniel's been at the end of his tether for weeks now—he has seriously got to get a different job! The baby's been crying all morning, and I haven't slept properly in days. I'm just at the end of my tether!

at the end of your tether

COMMON If you are at the end of your tether, you are very upset because you are no longer able to deal with a difficult situation. I had tried every solution I could think of: I was at the end of my tether.

at the end of your tether

having no patience, resources, or energy left to cope with something.

A North American variant of this expression is at the end of your rope , and in both cases the image is that of a grazing animal tethered on a rope that allows it a certain range in which to move but which at full stretch prohibits further movement.