Difficult carrying on later today (7)
I believe the answer is:
tonight
'later today' is the definition.
(I've seen this before)
'difficult carrying on' is the wordplay.
'difficult' becomes 'tight' (similar in meaning).
'carrying' is an insertion indicator.
'tight' placed around 'on' is 'TONIGHT'.
(Other definitions for tonight that I've seen before include "On tight (anag.)" , "Late today" , "Hotting (anag.)" , "late in the day" , "Got thin (anag)" .)