I do not get hangovers.

I’m a heavy drinker about 12 oz of whiskey a night or more on the weekends. Nothing else, just straight whiskey on ice. Why? Because my bills are paid and theres nothing left to do. I can get so fucking hammered and wake up the next day fine, ive had hangovers in the past but after a glass of water its fixed. Is this normal? I eat a relatively healthy diet lots of seafood and black coffee (which i read counteracts some of alcohols damaging effects on the liver) but yea I dont get hangovers