"Do I wake or sleep?"

"Adieu! adieu! thy plaintive anthem fades
Past the near meadows, over the still stream, 
Up the hill-side; and now 'tis buried deep
In the next valley-glades: 
Was it a vision, or a waking dream?
Fled is that music:--do I wake or sleep?"

--from John Keats' To a Nightingale