Mubble-Fubbles or Mubble Fubbles
Noun. Depression or low spirits. [from Words and phrases of the past ]
Noun. A state of depression or melancholy; despondency, low spirits. Chiefly in (also out of) one’s mubble-fubbles [from OED]
First heard of it in The Passive Voice. It seemed such a great word and made me smile.