in a funk

in a (blue) funk

sad; depressed. I've been in a blue funk all week. Don't get in a funk about your job. Things'll get better.
See also: funk
References in classic literature ?
Lop-Ear was plainly in a funk, and yet his conduct in remaining by me, in spite of his fear, I take as a foreshadowing of the altruism and comradeship that have helped make man the mightiest of the animals.