What's wrong with me.

I don't know why I used to do this. I remember being really young, like I was 10 and my brother was 4 I think. I was really hateful and rude towards him, whenever we interacted I made him cry. I was such a prick back then, I wonder how my parents didn't bother to even console me on how I keep getting mad, but at the same time, it's them, so I expect them to act apathetic. The weird thing was that before I used to be so kind, I really acted like a big sibling. I used to sleep in the same bed as him to comfort him, I used to explain everything so patiently, I used to cradle him. I don't know what's wrong with me now. I just feel the instinctive urge to hate on him, I would have to physically hold myself back from verbally fighting him whenever he spoke now. It all started when he finally learned how to hug, it all went downhill when he learned how to show love and affection. It felt scary. I associated my name being mentioned across people being a bad sign, so I was always so anxious and scared whenever he opened his mouth. I remember people praising me over something, but they weren't talking to me, they were putting me in a casual conversation. I remember being so scared that I ran and hid in my room for hours until they had to call me for dinner. I don't remember a time where it wasn't like that, where I wasn't running from what seemed to be the only adult figure in the house and crying alone because I had no one to comfort me. Obviously I've been better, I feel better atleast. I'm no longer anxious when people mention me or even badmouth me, I don't feel the urge to run away or hit someone for showing their love to me, and more importantly, I'm learning how to be kinder towards my little brother now.