After break I have become fidgety (7)
I believe the answer is:
restive
'fidgety' is the definition.
(synonyms)
'after break i have' is the wordplay.
'after' means one lot of letters go next to another.
'break' becomes 'rest' (a rest is taking a break).
'i have' becomes 'I've' (contraction of 'I have').
'rest' put next to 'ive' is 'RESTIVE'.
'become' acts as a link.
(Other definitions for restive that I've seen before include "Unable to keep still" , "Fidgety, uneasy" , "Unsettled" , "Impatient - jumpy" , "Uneasy, nervous" .)