Same Day Hangover

Has anyone else experienced this phenomenon? Getting a hangover the very same day, rather than the next day? This would assume that you had been drinking rather early in the day, say, starting at 3:30 or so, having cocktails at Soho Grand. Not that this is something I do often. But I did it today, and my god almighty do I ever have a splitting goddamn headache. And I've gotten same day hangovers before, days when we have a happy hour of sorts at work. Fuck I think I am even nauseous. Fucking hangovers. Demon alcohol. And I only had three drinks!