Fat loss or embarrassment for the rest of my life

I need to lose fat really fast I'm 200 pounds and 5'5". How should I change my diet and should I only be doing cardio?? If any one has secrets it'd be great. Please someone help me I'm tired of being called fat everyday I know I am already. And im 10000% ready to change that. I eat three times a day. Don't drink enough water. And eat bad (chocolate, fried foods)