Select the most appropriate idiom to fill in the blank.
When I went to Egypt and lost my wallet and passport, I was _____________.

The correct option is "up in a creek without a paddle".

Let's analyze the context of the sentence and the meaning of the given idioms:
The sentence describes a highly difficult and troublesome situation: traveling in a foreign country (Egypt) and losing crucial items like a wallet and a passport. This leaves the person with no money, no identification, and no easy way to travel or return home.

Now let's examine the meanings of the options to find the one that fits this context:
1. "rolling up my sleeves": This means preparing to work hard or getting ready to tackle a difficult task.
2. "putting my nose to the grindstone": This means working hard and focusing intensely on one's work for a long period.
3. "working my fingers to the bone": This means working extremely hard, often to the point of physical exhaustion.
4. "up in a creek without a paddle" (a variation of the common idiom "up a creek without a paddle"): This means to be in a very difficult, helpless, or troublesome situation without any obvious way to get out of it.

Losing your wallet and passport in a foreign country puts you in a highly vulnerable and difficult position with no immediate means of help, which perfectly matches the meaning of being "up in a creek without a paddle".