Let me tell you what I do. I work alot, and I go to school, and I workout every morning, and have a life. so, yes, I am busy too. In fact, most people are. this is what I do, take it as it is:
If I know I will not be home all day, which happens alot, I pack ALL my food in a lunch box that I keep with me. BUT before I can pack it, I have to cook everything. Yes, cooking is very important if you want to have a lean body. So, after I drive to and back from the gym, I usually have 45 mins to get ready and be out the door. First thing I do when I get home is start a batch of brown rice (enough for 2-3 meals) and cook a couple chicken breasts on low heat. Then, I jump into the shower, and get dressed, in 10 mins. (yes, you have to be fast) get out, and my rice is perfectly cooked, and the chicken breasts are done. I have only burnt my chicken once, you just have to cook it slow. Practice with the timing, and you will get it down. Then, I have to cut everything up, (veggies, meat) and place them in separate containers. ALSO, tuna is GREAT! I always have a can opener in my lunch box with a couple cans of tuna, and theres a great source of instant protein. I also use protein bars, and shakes.
You have to find something that will work for you. "not having time" is not an option. Do it the night before, or cook your food 1 week in advance. I cook it in the morning because Its fresher, but do what works for you. You sound like you are really new to serious training. And you are really young. (which is not a diss, just pointing it out) so your probably a little overwhelmed, but hey most people are when they first start! ( I still am!)
To really get lean, you need to find out alot about nutrition, and training. Get a couple books from the library, do some research. If you just want to "lose weight" then don't worry about nutrition, you can lose weight on slim fast. But, that will not get you lean, and is not serious nutrition. But I'm assuming you want to get lean and have a hot body right? It takes work, not just in the gym, but in the kitchen. If you want a six pack that the girls in your school with be drooling over, it won't happen by just "losing weight".
Keep it simple:
Have 6 small meals a day
1 portion of protein, 1 portion of carbs
Drink at least a gallon of water a day
eat as many green veggies as you can
( a portion is the size of your fist)
Plus, rotating days of weight training/cardio
That's just a very simple plan to start out with. But, with the more knowledge you have the better results you can get, and more "educated questions" you can ask.
Of course stick to pure foods, that are high in vitamins/nutrients.
Chicken,tuna,turkey,sirloin,protein powder
Oatmeal, brown rice, wheat pasta, fruit,
Hope that gives you a little more help in your quest. Like I said, theres alot more to fitness then that, but I hope that gives you a basic understanding of it.
Wish you the best!