In bed, more annoyed (8)
I believe the answer is:
bothered
'annoyed' is the definition.
('bother' can be a synonym of 'annoy')
'in bed more' is the wordplay.
'in' is an insertion indicator.
'more' becomes 'other' (synonyms).
'bed' enclosing 'other' is 'BOTHERED'.
(Other definitions for bothered that I've seen before include "Under stress" , "Was a pest" , "Old song: 'Bewitched, . . . . . . . . and bewildered'" , "Disturbed" , "Made an effort -- put out" .)