Gracious, there's a terrible rise in unhappiness! (6)
I believe the answer is:
misery
'unhappiness' is the definition.
(I've seen this before)
'gracious there's a terrible rise in' is the wordplay.
'gracious' becomes 'my' (I've seen this in other clues).
'there's a terrible' indicates an anagram.
'in' indicates putting letters inside.
'rise' is an anagram of 'iser'.
'my' placed around 'iser' is 'MISERY'.
(Other definitions for misery that I've seen before include "Great suffering" , "Intense unhappiness" , "Despair" , "Wretched conditions" , "''. . . . . . loves company''" .)