sounds like you should eat a bigger breakfast, or just eat more altogether.
i find that real food (eggs/bacon/toast/cereal/etc as opposed to clif bars or gels) in the morning gives me the energy i need for most of the day. then you can do light snacking on top of that, but you need a good foundation (of food) to go on. least i do.
best of luck! i hope i'm still pedaling when i'm that young. =]