Affiliate Marketing Secrets

I’ve been best friends with this girl since the seventh grade. (We’re seniors in high school now.) And we’ve never fought or had any problems with each other, but now I can’t seem handle being around her.
She’s always been smart and hilarious and beautiful and confident and creative and interesting. She can talk to anyone and have them like her in seconds, including adults. I admit that I kind of envy her a little, but I try not to compare myself to her. It’s just getting harder now that we have classes together. I was really good at English last year (highest class grade, essays used as samples), but we have English together now, and she seems to have taken my place there. We’re also in the same art class together. My confidence in my work has always been pretty low, but now it’s worse because my friend demonstrates a talent far superior to mine. Having her there makes me even less confident in my work because I can’t stop comparing my stuff to hers. It’s terrible.
It’s gotten to the point at which I’ve stopped talking to her as often, and stupid things she says or does make me overreact in anger. I’ll think she’s a know-it-all or an attention-whore or horrible things like that, which I know isn’t my honest opinion, but I guess I’m just jealous.
I’ve explained it to myself as us trying to occupy the same niche. We’re both artistic, good at English, we have very similar humor, we both like to look at the world in the same kind of weird way, we behave pretty similarly. When she’s there, she takes that personaity niche, and I just kind of let her and stay quiet and reserved. But today she was absent, and I felt so much more myself and talkative and outgoing, because that niche was there for me to take. I got to play her role.
I know, it sounds crazy. I have no idea why I find our similarities threatening.
What can I do? How can I stop feeling repressed when she’s around? How can I stop comparing myself to her?
Thanks.