Why do i feel guilty after eating every meal?

I have no idea what is wrong with me, i've been dieting for around a year? I've lost nearly 3 stone (around 40 pounds i thing) but after every meal, healthy or not i feel unbelievably fat and discusting, i feel like i want to stick my fingers down my thoat and throw everything up or excerise for hours! Like today i've had so far
breakfast: chopped up green apple, chopped up banana and natural fat free yogurt
but i felt fine after that.
snack: i had a flapjack because i baked them and i feel Really Really fat and that i shouldnt eat for the rest of the day and i've already been for a 1 mile jog, cardio excerise like jumping jacks and squats, press ups and crunches
i'm going to do a zumba work out soon because i still feel horrible! Sometimes even if i have an apple or veg or fish i feel really fat, what's wrong with me? I'm not going to eat any lunch because i feel disgusting about myself. Also i use an app on my iphone called myfitnesspal.com and it lets you count all your calories and i have a goal of how many calories i should take in 1 day and i've set 800 for me, is that healthy? But i normally only have arounf 450-500 rarely more. I just wish i was like all my friends who can eat candy and cookies and chips and not worry about there weight.btw i'm 14, 5ft and i weigh around 107 pounds.

I would see your doctor or a counsellor because it sounds like you have an eating disorder, most likely anorexia nervosa. If you speak to them sooner rather than later they will be able to help you come up with a way of managing how you feel.

800 calories are not going to help you… You did the same mistake which normally everyone does I. E. You only burn calories and not fat. You should consume around 1500-1800 calories atleast. You can't leave anything. You should have cheat days like 1st or 2nd sunday to eat whatever you want to. If you leave it permanently your body isn't going to accept it and will make you ill. You should eat healthy while exercising too

Take up a hobby like jogging or working out. You will feel alot better about yourself and you need those calories.