At first, egg husband to sort out performance anxiety (5,6)
I believe the answer is:
stage fright
'performance anxiety' is the definition.
(anxiety about performing on stage)
'at first egg husband to sort out' is the wordplay.
'husband' becomes 'h'.
'to sort out' indicates anagramming the letters.
'at'+'first'+'egg'+'h'='atfirsteggh'
'atfirsteggh' is an anagram of 'STAGE-FRIGHT'.
(Other definitions for stage fright that I've seen before include "Nerves in front of an audience" , "problem for players" , "Panic experienced by performer" , "Actor's fear" , "attack of nerves" .)