up a creek

up a/the creek (without a paddle)

slang In a challenging or troublesome situation, especially one that cannot be easily resolved. I have no savings, so if I get fired from my job, I'll be up the creek without a paddle. Shouldn't we stop for gas? We'll be up a creek if the car dies on that desolate road ahead.
See also: creek, up
Farlex Dictionary of Idioms.

up a creek

Also, up shit creek; up the creek (without a paddle). In trouble, in a serious predicament, as in If the check doesn't arrive today I'm up a creek, or The car wouldn't start, so I was up the creek without a paddle. This slangy idiom conjures up the image of a stranded canoeist with no way of moving (paddling) the canoe. President Harry S. Truman used the first term in a letter in 1918. The first variant is considered vulgar.
See also: creek, up
The American Heritage® Dictionary of Idioms by Christine Ammer.

up a creek

verb
See up shit creek without a paddle
See also: creek, up
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • be up a/the creek (without a paddle)
  • be up the creek without a paddle
  • be in deep water
  • in deep water
  • in deep water(s)
  • get in(to) deep water
  • in hot water
  • get out of a jam
  • get out from under (someone or something)