if it's red wine there may be good reason
the darker the brew (Guiness seems to be one of those exceptions) the more congeners (fusel oils - non ethyl alcohols - call them what you will).
These obscure alcohols are harder for the liver to digest and clog it up. Hair of the Dog works (according to New Scientist) because the liver digests ethyl in preference so it spreads the digestion of congeners over a longer time.
They also recommended L Cystene which increases the metabolism & gave me the kind of indestion you get from neat whiskey.
my problem relates to a couple of pints of cider and is not what you would call a hangover so my experiences are atypical.