Affected by a tinge of nostalgia in middle of poem (5)
I believe the answer is:
tween
'nostalgia in middle of poem' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'affected by a tinge' is the wordplay.
'affected' becomes 'twee' (I've seen this before).
'by' means one lot of letters go next to another.
'a tinge' becomes 'n' (I am not sure about this - if you are sure you should believe this answer much more).
'twee'+'n'='TWEEN'
'of' acts as a link.
Can you help me to learn more?
(Another definition for tween that I've seen is " In middle of abridged".)