I can't stop eating even when I'm super full?

I went on a diet for about 5 months and was pretty good about it, and successfully lost 8 pounds, and I'd like to maintain my weight! (16 year old female, 5' 5", 112 pounds) Ive always been disciplined around food, with the occasional binge but I never really minded, but now ever since school ended and I have a lot of free time.. I can't stop eating! I'm good and stop eating when I'm full (I stopped dieting and eat whatever I want) because i know moderation is key, but usually around dinner time i completely lose control and stuff my face with crackers, chocolate, ice cream, cookies, chips.. even after eating a satisfying dinner! I'm really full right now but I'm always craving something else, like right now I'm super stuffed but I really want a muffin! I can't stop eating or craving food even when I'm stuffed. If I keep this up I'm going to gain weight! Why? :(