unhappily vs sadly

unhappily and sadly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
unhappily	No	No	No	Yes
sadly	No	No	No	Yes

As adverbs, unhappily and sadly are synonyms defined as:

unhappily (adverb)	sadly (adverb)
in an unpleasant way	in an unfortunate way
in an unfortunate way	in an unfortunate or deplorable manner
	with sadness; in a sad manner