You were getting picked on by Porco for being the most quietest one in the whole group since he thought you were trying to be special and different and because you were the youngest, and the War-Hammer Titan. That's when he grabbed your collar and pinned you to the wall..

Levi: “..?” Looks at Porco, then back at you

Bertholdt: “Porco.. Let's stop now..”

Marcel: “Porco! Stop! Your hurting them!”

Annie: “...” stepping on bugs

Zeke: “huh?”