Terrible time alone in shelter (4-2)
I believe the answer is:
lean-to
'shelter' is the definition.
(lean-to is a kind of shelter)
'terrible time alone' is the subsidiary indication.
'terrible' indicates an anagram.
'time' becomes 't'.
't'+'alone'='talone'
'talone' anagrammed gives 'leanto'.
'in' is the link.
(Other definitions for lean-to that I've seen before include "Penthouse" , "Rough shelter lying against the wall of a building" , "Building added to another" , "Outhouse" , "Shed, outbuilding" .)