Stop caffeine and reduce sugar. It's amazing how calm and in control and content you feel when you get off the stuff. It's a horrible addiction.
But if you must go to the health store and get some green tea tablets. Much better for you and the green tea has some health effects too.
Then go to GNC and get that megamen Multi vitamin:
http://www.gnc.com/product/index.jsp?productId=4033435
Take one of those and then an hour later take the green tea tablet. Man you'll be flying with energy and ambition, and good energy. You'll be a lot healthier for it and no crash.
But get off the other stuff first. Just use these two. A chocolate here and there ain't to bad though. Just as a treat not as something regular.