forever vs everlastingly

forever and everlastingly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
forever	No	No	No	Yes
everlastingly	No	No	No	Yes

As adverbs, forever and everlastingly are synonyms defined as:

Other synonyms of forever include eternally, evermore.

forever (adverb)	everlastingly (adverb)
for a limitless time	for a limitless time
for a very long or seemingly endless time
invariably