ok to bulk your gonna have to eat alot. now i know its gonna be hard for you since the issue about you gaining weight but putting on size doesn't come without hard work and dedication. before you take the next step you have to put it in your head that your gonna do whatever it takes including eating and when i say eating theres gonna be times when you say i cant but you have to put it in your head that this is what you want.
so im gonna set up a schedule for you that should work with your school
7am breakfast im thinking 4 egg whites a day with some fresh fruit or veggies.
10am in between your classes try to get a protein shake in. muscle milk is a good ready to drink shake that can stay warm but can get
pricey. you can get some powder and leave it in a shake mixer and add water and down it before your next class but shakes with water tend to taste like shit. its up to you what you use but make sure you get that protein in.
12pm you prob have lunch around noon don't eat the shit they serve you at school, if its like what we use to have there is nothing good in it. pack a lunch you can do boiled chicken breast or make a cold cut sandwich jus make sure it has enough meat in it to get your protein.
3pm have another snack peanut butter works or some tuna will be good. if you get tuna dont mix in any mayo if you cant stand the taste of it you can add in some lemon juice and chop some celery and add it to it.
6pm have dinner eat a normal dinner with the family anything goes jus make sure you have some protein in it
before you go to sleep drink a shake.
so thats a basic eating schedule for you i dont know what time you go to the gym so your gonna have to work your eating schedule around it. jus make sure that you wait 1 - 2 hours after you eat to work out and u wanna have a shake right when u get out of the gym.
i wouldn't take any supplements right now jus make sure you take some kind of multi vitamins.
also jus so you know how much protein to take in at your age you want at least 1gram per pound you weigh with a max of 1.25grams.
for you gym schedule try this
monday chest and triceps
tuesday shoulders, traps, squats
wednesday back and bicep
thursday chest
friday triceps, biceps and cardio(20 min)
try it for 2 weeks and come back and let us know how it goes