I'm soon upset by the East - it's disgusting (7)
I believe the answer is:
noisome
'disgusting' is the definition.
(I've seen this in another clue)
'i'm soon upset by the east' is the wordplay.
'upset by' is an anagram indicator.
'the east' becomes 'E' (abbreviation).
'im'+'soon'='imsoon'
'imsoon' anagrammed gives 'noisom'.
'noisom'+'e'='NOISOME'
'it's' acts as a link.
(Other definitions for noisome that I've seen before include "Unpleasantly smelling" , "Odorous" , "Disagreeable - noxious" , "Obnoxious" , "Offensively smelling" .)