Hey, it's because of the sugar that was in the alcohol, and your body is not used to it. The book Potatos not Prozac gives a good explanation of sugar and alcohol, and how to regulate your systems so we no longer have those cravings. If you dont want to read the book then try eating 3 meals a day without any sugar, but have lots of protein and high fiber carbs at each meal. This should help with the regulating, and in the meantime drink lots of H20