How Exactly Should I Balance My Diet?

I think I eat way too much candy, cookies, etc. Than other people. I hardly eat meat, unless it's chicken, and I always have a small portion of veggies when my parents cook. I usually skip breakfast and go straight to school, and I have dinner, but it's not like a family dinner where there's a big pot of food. (my parents work day to midnight) And I can't make my own food if it's not microwavable, or straight out of the fridge. So to fill my stomach up, I always have a bunch of snacks (pocky, oreos, rice krispies, muffins, etc) And eat them whenever I feel hungry. I'm not fat, and I didn't gain weight for the last few months, I seem healthy, but am I really? Should I eat more grain, or meat, or protein? I already drink milk (my fav xD) so that's out of the question, and my parent's don't have time to teach me how to cook, since they take care of my baby brother their whole extra time...what should I do?