I keep getting severe headaches every night at the same time after having a glass of red wine and dinner?

It's a migraine: Wine is a common migraine trigger. Cluster headaches are also triggered by alcohol and often occur at the same time every night, but they usually start immediately after ingesting alcohol. Sulfites occur naturally, but are also added to wine as a preservative and are at least in part are responsible for headaches. Vodka is less likely to cause headaches because it is pure alcohol, but it also can.