Bad headache from one rye, perhaps, consumed by me (8)
I believe the answer is:
migraine
'bad headache' is the definition.
(I've seen this before)
'one rye perhaps consumed by me' is the wordplay.
'one' becomes 'i' (Roman numeral).
'rye perhaps' becomes 'grain' (rye is a kind of grain).
'consumed by' is an insertion indicator.
'i'+'grain'='igrain'
'igrain' going within 'me' is 'MIGRAINE'.
'from' is the link.
(Other definitions for migraine that I've seen before include "A really bad headache" , "Crippling headache" , "misery in capital area" , "A really nasty headache" , "Severe recurring headache" .)