One thing you didn't say in your e-mail was whether your friend seems to be trying to compete with you. Like, if you're getting attention from someone else, does your friend try to insert herself in the middle and steal your thunder? Or, if you show up wearing a cute new outfit at school, does she run out and buy the exact same one, every single time? Sometimes, when people do things like that, it can be so subtle that's it's hard to realize at first. All you know is that you feel weird and uncomfortable, but you don't know why. If your friend is pulling stuff like that, you may want to rethink how much time you spend with her. Or, if her friendship is important to you, examine possible reasons for her behavior. Realizing that her competitive nature is due to her own insecurities may help you cope.

However, we are going to assume that this is less about your friend and more about your own insecurities. You sound like you don't have the best sense of perspective about your own looks and style, otherwise you wouldn't feel so badly that you have a girlfriend who looks good. When you're around her and start to feel down on yourself, make an effort to remind yourself that you are pretty amazing, too. It might help to make a list of all the things you like about yourself, whether it's your eyes, your infectious giggle or your great athletic ability. You can't be second best at everything! Also, there's nothing wrong with admitting to your friend that you sometimes feel a bit envious of her. She may surprise you by revealing that she has her own moments of wishing she had your gorgeous smile, killer arms or amazing dance skills. Most of all, it's important to remind yourself that there's room for both of you to look good. Just because she shines doesn't mean you can't, too!

—Andrea Pyros