Diets PLEASE help

Hey, girls! I just want to start off by saying I SUCK at diets. I started about a week ago and Ive already broken it three times. I just finished off my sisters ice cream. ugh! I’m not supposed to eat diary, gluten, or sugar. I think I started too big. PLEASE give me inspiration to continue on and maybe some encouraging words about not purging! I’m 200lbs and 5’7 so I REALLY need this but it’s hard...

EDIT: thanks y’all for your help!!!!