end of one's tether
{n. phr.}, {informal} The end of your trying or imagining; the last of your ability, or ideas of how to do more.
Frank was out of work and broke, and he was at the end of his rope.

The doctor saw that Mother had reached the end of her tether, and told us to send her away for a holiday.
Compare: AT ONE'S WIT'S END, FED UP, UP AGAINST IT, UP A TREE.

[TahlilGaran] English Idioms Dictionary ▲