Feel anxious after change of leader (5)
I believe the answer is:
sense
'feel' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
(Other definitions for sense that I've seen before include "Eg, sight, smell" , "Perceive; meaning" , "Meaning of a word or expression" , "definition" , "Be vaguely aware of" .)