please help me out!

hi i'm Allie and i really needed to vent today so i came here. all my friends look like models and a couple actually are! they all look perfect. i always look like a blob when i stand next to them. they always compare their weight to mine. and i know what they mean. they mean it like "bigger" then i'm supposed to be. i want to tell my teacher about it cause he make me feel comfy but i don't want my parents to know and i know he will be worried about me and tell them. what should i do??