I'm sad, wandering at large and miserable (6)
I believe the answer is:
dismal
'miserable' is the definition.
(thesaurus)
'i'm sad wandering at large' is the wordplay.
'wandering' indicates an anagram.
'at' is a charade indicator (letters next to each other).
'large' becomes 'l'.
'im'+'sad'='imsad'
'imsad' with letters rearranged gives 'disma'.
'disma'+'l'='DISMAL'
'and' is the link.
(Other definitions for dismal that I've seen before include "Dreary, cheerless" , "Dull and dreary" , "not a cheerful outlook ..." , "Very disappointing" , "Depressing; dreary" .)