Upset, sadly, about first of exam hold-ups (6)
I believe the answer is:
delays
'hold-ups' is the definition.
(I've seen this before)
'upset sadly about first of exam' is the wordplay.
'upset' indicates an anagram.
'about' is an insertion indicator.
'first of' indicates taking the first letters.
The initial letter of 'exam' is 'e'.
'sadly' anagrammed gives 'dlays'.
'dlays' enclosing 'e' is 'DELAYS'.
(Other definitions for delays that I've seen before include "Stays or postponements" , "Stoppages" , "Hinders; puts off" , "Hold-ups or deferrals" , "Retards or procrastinates" .)