what you are experiencing isn't sunkist addiction but caffeine withdrawal. The best thing you can do is quit the intake of caffeine all together and symptoms should last no longer than 9 days. If you would rather not detox on caffeine (you should, you would be healthier) you can simply take caffeine pills so you can lower your sunkist intake
sources:
http://www.wisegeek.com/what-are-sym...withdrawal.htm
http://www.coffeefaq.com/site/node/11