How not to think of food !!!!?

I've been skinny ever since i was a kid,when i was 14-15 yo,i i used to weight 45 kgs,but when i reached 17,my weight now ranges between 52-53,and i really wanna go back to my old weight! I went on a diet a few months ago and i lost 5 kgs but now i gained all the weight back,and im back to 53 kgs. All i can think of is food calories food calories,and it's annoying me! everytime i come to have lunch or dinner,i always count what i want to eat and i keep asking my self should i eat junk or no! Any suggestions?