When you wake up this morning, drink not only water but get some electrolytes in ya. Grab a powerade or gatorade. Your body passed a lot of electrolytes alongside other toxins throughout the course of the constant pissing the night of drinking, and through all the puking.
Drinking a nice big bottle of powerade, and grabbing a little food if you think you can handle it, will lead to a faster recovery than drinking straight water. And don't drink anything that's going to dehydrate you.
And one of the purposes of drinking the water is to help push out the toxins that remain from imperfect alcohol metabolism, and those toxins are responsible for the hangover. But if you drink a LOT of water you will definitely push out salts too, so like I said.. a nice 32oz or even just a 20oz bottle of Gatorade, Powerade, or a 4:1 ratio sports recovery drink (carbs+protein) will be the best bet. Gotta be formulated for 'recovery' though. I have this power mix, from PowerBar, it's for recovery and has a specific blend in it. That stuff is gold for hangovers.