Example: My cell phone was locked in the car with my keys and wallet - I was at the end of my rope.
- at the loose end of an untethered rope (rescue)
- grabbed the short end of a shrinking rope (resource)
- ran out of ladder
- reduced to pennies and pocket lint
- bailing with a bottomless pail
- at the mercy of a slippery rope with no grip
- on the last strand of an unraveling rope
- watched the rescue party pass me by
Discussion: Different from “at the end of my tether” (see OED [a] above for distinction. Also sometimes thought to mean “I can’t take anymore.” I didn't address those here.