Fit and sure maybe but altogether too much (7)
I believe the answer is:
'too much' is the definition.
'fit and sure maybe' is the wordplay.
'and' says to put letters next to each other.
'maybe' indicates an anagram.
'fit' after 'sure' is 'surefit'.
'surefit' is an anagram of 'SURFEIT'.
'but altogether' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for surfeit that I've seen before include "Excess, glut" , "Overindulgence" , "it's more than one needs" , "having had quite enough" , "Fustier (anag)" .)