Why everytime when I finish eating my stomach looks big and weird like if I had a ball inside of me? Is that normal?

Maybe, maybe not. A person whose stomach looks like a ball after eating, especially like a round soccer ball instead of an oblong football, would appear unusual. Even the stomachs of very slim people blend into their body contours after a big meal (but their tummies do seem bigger & firmer after eating). The person can make an appointment for after a big lunch, and show his doctor the ball-shaped tummy.