Drove one mad; it's so mawkish (11)
I believe the answer is:
sentimental
'so mawkish' is the definition.
'sentimental' can be an answer for 'mawkish' (synonyms). I am not sure about the 'so' bit.
'drove one mad' is the wordplay.
'drove' becomes 'sent' (I've seen this in other clues).
'one' becomes 'I' (Roman numeral).
'mad' becomes 'mental' (mentally ill).
'sent'+'i'+'mental'='SENTIMENTAL'
'it's' is the link.
Can you help me to learn more?
(Other definitions for sentimental that I've seen before include "with emotional effect" , "pathetic" , "With tender, nostalgic or sad feelings" , "Moved by fond memories of the past" , "Expressing tender emotions" .)