This person is my brother, he keeps talking to me, and I know he doesn’t have bad intentions, it’s just that I’m asking him to leave me alone a lot more, and I don’t want to hurt his feeling but at the same time, I just can’t deal with his voice after a while, I don’t know, my breathing gets quicker, I have to sit down, and I just start crying. I don’t want to be rude about it, but I feel like I am being rude by randomly crying or getting angry at him simply talking. I don’t want to do that to him, I just… do. What do I do?

Depending on his age you might be able to just explain it to him, which granted doesn't solve that problem, it would just be a case of reassuring that it isn't his fault entirely, otherwise you should gently nudge him towards his room/out of yours, just be gentle with him, and if you feel this bad about it make up for it when you can, but he'll still love you the same either way, I'm sure