But I actually wanted to link to Larry's Pretty Good Word of the Day. Uhtcearu - n., (obs.) lying awake worrying before dawn.
"...to break that down to its Old English components, uht(a) is the last hour of the night, just before dawn, and caeru is the ancestor of care in the sense of concern, which at the time had added meanings of anxiety/sorrow. This is used (in surviving records) only once in Old English, which makes it a hapax legomenon, but has been reappearing in word lists of interesting forgotten words in its nominative plural form, uhtceare."
Old English poetry likes to stick words together to express lovely ideas. Like its descendent German, but not nearly as thumpingly.