What does "My nerves are shot." mean?

Question

What does  "My nerves are shot."  mean?

Answer

meaning:
  in bad condition because of being used too much or treated badly:
  My nerves were	 shot to pieces	 after my driving test.

Answer

this is a fixed expression.

in this sentence, "to be shot"  means to be "to not work anymore because of overuse".

in this sentence 'nerves' means our emotional state.

so this means, "right now my emotional state is very bad, I am not comfortable and very anxious". something like that.