Called for in sad distress about a terrible half week (5)
I believe the answer is:
asked
'called for' is the definition.
('ask' can be a synonym of 'call for')
'sad distress about a terrible half week' is the wordplay.
'distress' indicates an anagram.
'about' is an insertion indicator.
'a terrible' indicates anagramming the letters.
'half' suggests halving the letters.
'sad' with letters rearranged gives 'asd'.
'week' cut in half is 'ek'.
'ek' anagrammed gives 'ke'.
'asd' going around 'ke' is 'ASKED'.
'in' acts as a link.
(Other definitions for asked that I've seen before include "Demanded" , "Questioned" , "Requested" , "Enquired; invited" , "Put a question to" .)