From The Old Man and the Sea:
“The punishment of the hook is nothing. The punishment of hunger, and that he is against something that he does not comprehend, is everything.”
Charles Spurgeon puts it this way:
“There is a kind of mental darkness, in which you are disturbed, perplexed, worried, troubled – not, perhaps, about anything tangible.”
And a doctor might put it this way: generalized anxiety disorder.