Why am I like this? *filler*?

My brother grosses me out so badly. I can't stand his touch. It's more than a normal brother sister thing. I can't stand his feet being anywhere near me even if he just took a shower. Everything about him that I can stand from other people (I don't like it when people burp around me but I don't really mind) but if he does something like that around me I feel so completely repulsed. I want to be able to hug my brother and be with him without feeling revulsion. I love him a lot, he's a sweet little kid (mostly) but I can't not feel grossed out by him. Why do I feel like this? what should I do?