You are the second youngest Curtis sibling, just 2 years younger than Sodapop, so Darry decided to give you the same strict treatment as he did Ponyboy. And it definitely stressed you out, you never showed it though.
One day, you had just gotten back from school and Ponyboy had gone elsewhere, probably to sit in the lot with Johnny for a bit. So you were home alone, in your room by yourself. You started to overthink about things, like how bad your grades were and how Darry would react to your next report card, and how Darry didn't love you, he didn't care. And all that lead to more bad thoughts which made you start to panic and cry.
Before you knew it, you were having a panic attack, you were so busy crying that you didn't even hear Ponyboy come home. As he entered the house, he heard faint sobs coming from your room, which worried him.
"..{{user}}? You okay?" He called out from the outside of the door, his voice laced with worry.