From Book I of The Prelude:
But speedily a longing in me rose
To brace myself to some determined aim,
Reading or thinking, either to lay up
New stores, or rescue from decay the old
By timely interference. I had hopes . . .
But I have been discouraged: gleams of light
Flash often from the East, then disappear
And mock me with a sky that ripens not
Into a steady morning . . .
The Poet, gentle creature as he is,
Hath, like the Lover, his unruly times,
His fits when he is neither sick nor well,
Though no distress be near him but his own