Funk. In a funk or blue funk, To be. The word may derive from Old French funkier, ‘to smoke’, though the connection is uncertain.  A funk is a state of apprehensive fear or abject fear.  The word first appeared at Oxford in the first half of the 18th Century.

“If I was going to be flogged next minute, I should be in a blue funk.” – THOMAS HUGHES: Tom Brown’s Schooldays, Pt I, ch ii (1857)

– Brewer’s Dictionary of Phrase & Fable, Sixteenth Edition revised by Adrian Room.