Strange Hunger...

I've began to notice some strange eating patterns lately. I will feel ravenously hungry, and once I start eating, my body is like sending me a message saying stop eating, now. I'm 19 years old, 5'2", and weigh 125. Since this began, I feel like I'm losing weight because of it. My tongue also feels funny after I'm done eating. I've also noticed some strange symptoms while I have this "hungry" feeling. I feel really weak, I feel somewhat cold, I also always feel the need to sit down, also feeling some sweat forming.  I noticed a couple of days ago (I go to a culinary school) I was in the kitchen, and my class went somewhere. The minute I sat down, I felt the same symptoms all over again. When I got back to class, I had to sit down cause I feared I was going to pass out. Whenever I go eat, I would get my food, and only eat a 1/3 of it. What's going on with me?