Hi. My Name Is Michaela. I Want To Know. Why

Hi. My name is Michaela. I want to know. Why I'm keep hungry when I eating then I was became full. About 10- 15 mins later, I getting to become hungry again. I keep eating a food, again. I want to stop eating. I'm concern about my health system develop.. Started since three months. My family and friends tried to stop me. i kept stubborn eating. My habit food are mostly health and junk. i kept drinking water, pop, and juice,and less milk. I think that I get allergy of Milk. I'm regular skinny. My weight is average 105- 110. I never get gain my weight. Sometime, finally i get a bit little gain like 5 pounds then few hours later, lose weight again. I don't know why keep lost weight. It'd never get gain weight.. I'm a skinny! I'm so frustrated with my habit foods. Please the answer for my question? email to me very soon? Thank you!