To try new activities somehow was depressing? No (6,4,5)
I believe the answer is:
spread ones wings
'to try new activities' is the definition.
'somehow was depressing? no' is the wordplay.
'somehow' indicates anagramming the letters.
'was'+'depressing'+'no'='wasdepressingno'
'wasdepressingno' with letters rearranged gives 'SPREAD ONES WINGS'.
(Other definitions for spread ones wings that I've seen before include "Try something new" , "make full use of one's talents" , "as a high-flyer would?" , "Develop abilities fully" .)