Sentimental, recollected losing cat (9)
I believe the answer is:
nostalgic
'sentimental' is the definition.
(thesaurus)
'recollected losing cat' is the wordplay.
'recollected' is an anagram indicator.
'losing'+'cat'='losingcat'
'losingcat' is an anagram of 'NOSTALGIC'.
(Other definitions for nostalgic that I've seen before include "Wistful" , "Longing for something past -- at closing (anag)" , "longing for home" , "recollection?" , "Home sick" .)