Lose weight and muscle

Now that summer has started I am always busy with school and work. Because of this I can only eat the same as before, I have a loaded program that allows me to have only 2-3 meals a day and it does not seem to consume the necessary calories. I feel bad it took me 2 years to develop my muscle and now I lose it because of the time. I know it does not consume enough calories, can you give me some advice please? tried to raise the portions at the tables that we have but failed.Sorry for my bad english.