Why does this happen?

Every time I eat, even if its just a biscuit or something small, my stomach bloats so much, mainly around the waist/ribs. Why? I hate it and it makes me so damn self conscious. I've been trying to lose weight but I feel like there's no point because this happens anyway, and I binge all over again. The cycle is awful.

Before

After

Update :

I also started getting a very acidic and eggy taste in my mouth today and kept burping. I informed my dad and I now have some medication. Fingers crossed it'll all stop soon! I researched online and apparently overeating, chocolate, and soda can cause this. I have recently developed binge eating disorder after a span of eating 500cals a day, and I binged on chocolatey things, and on bad days drink about 3-5litres of diet sodas. Hopefully I can overcome this, stop these awful habits, and get my life and health back on track, ED free and body dysmorphia free also! 🌈 ♥️

Thanks for the help and support in the comments