I need help with my nutrition, I work out 3+ hours a day ( demanding work out) and I think it's my nutrition..?

Your nutrition is probably holding you back. You should try to eat more fruits and vegetables. You are suppose to eat 5 a day. Also you should skip all the fast food. That alone will help you alot. But are you trying to lose weight or gain muscle. If you are trying to lose weight you should avoid sugar, bad fats, and excessive carbs. If you are trying to gain muscle, you should eat lots of protein.