I know it will be unpopular because this is such a conservative, closed-minded forum, but the BEST, by far, is this.
1. Vomit if you need to, dont hold it back
2. Have a few sips of healthy drink (non alcoholic of course)
3. Share a spliff and dont have too much
4. Relax in comfortable clothes watching your favourite TV show, comedy/mindless sitcom is best. Drink lots of fruit juice
5. When you feel well enough, have a fry up.
6. As soon as your strength has returned, have sex. (failing that do whatever makes you feel good, other than drinking alcohol)
Spritiually speaking, just RELAX and reflect on how lucky you are to be able to go out and 'enjoy yourself' last night when there is so much suffering in the world. Besides, you are a human! Doesn't that just totally rule? Think about it!
Good luck with the head