Mine, with current flu treatment, is miserable (7)
I believe the answer is:
pitiful
'miserable' is the definition.
(I know that miserable can be written as pitiful)
'mine with current flu treatment' is the wordplay.
'mine' becomes 'pit' (down the pit).
'with' indicates putting letters inside.
'current' becomes 'I' (physics symbol).
'treatment' indicates an anagram (letters treated or processed differently).
'flu' is an anagram of 'ful'.
'i' inserted within 'ful' is 'iful'.
'pit'+'iful'='PITIFUL'
'is' acts as a link.
(Other definitions for pitiful that I've seen before include "Sad - wretched" , "Distressing" , "base" , "Miserable" , "Tiny" .)