Cravings are what drives an addiction, and can be an uncomfortable part of life for those who use in a more controlled manner.
Weekend bingers and long-term users on the wagon alike know that intense hunger to re-experience the euphoria, stimulation or relaxation that you were seeking when you got high.
There are three responses you can have to the cravings -- you can use again, which will provide only temporary relief, and will get increasingly unsatisfying. Using this option is a one-way street to drug dependence.
Alternatively, you can torture yourself by staying up all night, obsessing about how awful you feel, biting your nails, starving yourself or eating junk food, indulging in another addictive behavior, and generally feeling sorry for yourself. Not great, but at least you didn't use.
Or you can take the third path, and start to take care of yourself. These strategies will help you cope with the roller coaster of your drug cravings, and will also help you to start taking better care of yourself -- physically and emotionally.