Analysis of Sonnet XXXIX: Sleepless Dreams

Girt in dark growths, yet glimmering with one star,
O night desirous as the nights of youth!
Why should my heart within thy spell, forsooth,
Now beat, as the bride's finger-pulses are
Quickened within the girdling golden bar?
What wings are these that fan my pillow smooth?
And why does Sleep, waved back by Joy and Ruth,
Tread softly round and gaze at me from far?
Nay, night deep-leaved! And would Love feign in thee
Some shadowy palpitating grove that bears
Rest for man's eyes and music for his ears?
O lonely night! art thou not known to me,
A thicket hung with masks of mockery
And watered with the wasteful warmth of tears?