How come once i eat i cant stop!!!!?

k im 16, but ive been this way since as long as i can remember. like lets say im having tacos ill eat until there are no tortillas left and then ill find another way to eat the beans and cheese. im never hungry feeling or full feeling. ive felt full twice in my life, one of those times i was really sick with the flue. and the other i was at olive garden and ive eaten two or three plates of the salad my pasta and the three thing appetizer and an italian soda drink thing, its a 30 minute drive and about 10 minutes into it i felt hungry again. im just gonna assume something isnt connecting from my stomach to brain. im 5 foot 8 so that can have something to do with it but i eat more than the heavy set girls i know do. i have huge cravings and mood swings when i dont get the food i want when and how i want it. also uhmm like literally 2-5 minutes after i finish the food and theres none left i say things to who ever im eating with like "wow remember when those burgers just got here and we had a whole thing of fries i miss that" i cant help but think about how i want more the whole day. when im not eating im thinking about eating or talking about it. i know it probably annoys my friends that id rather tell them about what i had for dinner that night than how my date was. its true food is my favorite topic.