Why am i eating so much?

yesterday, my mom made a BIG dinner...i had 2 whole steaks, 2 crab cakes, 3 full spoons of mixed veggies, and a baked potato. Afterwords, i was STILL hungry. So then i had some cake a few hours later. So this morning i woke up, did my thing to get ready for school, ate a bowl of cereal, the usual for a high schooler. Then by 945am i was starving! i felt like i havent eaten in days. i started shaking shortly after. So i ate lunch at my scheduled time. i had a burger, slushie, and sorbert. i was fine for about 5 minutes and then i was hungry. so i came home and i ate a bowl of ice cream, sausage and potatoes (left overs). i was full for a few minutes, but then i got hungry. So my mom made dinner and she made chipped-beef, eggs, and potatoes. (we eat alot of potatoes) i had 3 serves of chipped-beef, 1 serving of eggs, and 2 serving of potatoes. but i was still hungry. my mom litterally made me stop eating! What is wrong? i read that it might be diabetes. which is possible considering all of my grandparents have it and my cousin does also. any other ideas? im 15 y/o currently 128 lbs. HELP!!!