Badly affected by success? (3)
I believe the answer is:
hit
This clue is a double definition.
'badly affected' is the first definition.
(hit hard)
'success?' is the second definition.
(I know that hit is a type of success)
'by' is the link.
(Other definitions for hit that I've seen before include "Strike, clout" , "that pleases the public" , "The shot < to > beat" , "Successful song" , "Successful record" .)