carbs are a source of glucose which is what your brain uses as fuel. they also fuel your daily activities, as we get little energy from protein - most of that is used for the construction of new tissue in our bodies (ie, new muscles, repairing injuries, maintaining muscle mass, etc), or fat (i can't remember right now what fat is used for.. it carries vitamins and minerals, acts as a lubricant and gives us some energy value..).. what i would worry about is getting too many REFINED carbs and not enough whole grains. I've seen what you eat every day, though, and you are doing GREAT. You eat a balanced diet with adequate fruits, veggies, and whole grains, and you're active enough to balance it all out..
don't worry, eat and be happy.