“Quit drinking.”
Funny, I think I promised God I would do that about 4:00 a.m.
I'm a recovering alcoholic and during my 17 years of hard drinking I had a few monumental hangovers. Of course, professional drinkers know to stick a bottle of Gatorade in the freezer the night before, and stick it under your pillow when you get home. The coolness stops the throbbing in your head and in the back of your neck, and by the time you wake up, it's pretty much thawed.
I only get flu symptoms every couple of years, but when I do, they hit me pretty hard, and it feels a lot like a hangover. When it does hit me, I'm still amazed that I used to inflict the exact symptoms on myself deliberately, and usually paid for the privilege!