Hit rock bottom and aspired to change (7)
I believe the answer is:
despair
'hit rock bottom' is the definition.
(thesaurus)
'aspired to change' is the wordplay.
'to change' is an anagram indicator.
'aspired' is an anagram of 'DESPAIR'.
'and' acts as a link.
(Other definitions for despair that I've seen before include "Be without hope" , "First appearance" , "Abandon hope" , "Give up hope" , "A spider (anag.)" .)