[cdacda13]

First off, re-hydrate yourself. That means water, gatorade, and green tea works great too. Throwing up is good, but make sure you fill the space back up with liquid.
Second, eat something as stated before. This will slow the rate that the alcohol absorbs in your stomach.
Third, take two aspirin. Although not the best thing for your stomach in the long term, it will help your headache quickly.
Fourth, Rest unless you feel decent.
Fifth, if your head still feels like its attached to your body, move around. A good work that gets the heart racing brings more oxygen into the body. The more oxygen, the faster you oxidize the alcohol in you liver and get it out of your body.

A hangover is actually two different things. Its your body going through alcohol withdrawal and dehydration.