Ive been great friends with this girl for 4/5 years but still feel she and I compete and I am certainly not a competitive person when it comes to friends. She is a great girl but has let me down in the past and on some occasions makes me feel less important to her than her other friends. Am I just insecure and what can I do to fix this?

Not sure if you are insecure. What types of things does she do? Does she try and one up you with everything you say and do? How do you feel she has let you down?

Wow. That's a good question. It's good that you can recognize this behavior in yourself, whereas many folks can't. Do you feel like you have to impress her in order to keep her friendship or attention? Are there characteristics that she possesses that you are envious of? I think that the heart of most competition is some form of insecurity that you have to achieve a certain goal or time limit in order to feel valued.
However, competition, if not done obsessively is not always a bad thing. It can drive you to do that extra bit that lets you stand out in a business setting or in the classroom. As long as there are no hard feelings between the two of you regarding your respective triumphs and failures, it shouldn't be a problem.
As to the fact that you feel she finds you less important, maybe she is not aware of your feelings on this topic. Do you feel comfortable speaking to her about it? Perhaps just a clearing of the air on the subject will make you feel a bit more secure in your place as her friend.
And if you don't feel comfortable talking to her about this, maybe she should be less important to you, instead of the other way around.
Good luck to you and if you have any questions or comments, let me know.
:-)
Kayti

She often cuts off my sentences, its like she always needs to have the final word. She has let me down when I needed her most, probably a silly incident whereby she would not give up a room she knew I deserved, and, knowing how I felt about it, rubbed it in my face. Maybe I am simply paranoid but she doesn't confide in me anymore and not sure why. Its like there is a barrier between us that onoy I see and while all of our other friends really love her (not saying I dont) I can't help but feel bitterness towards her in some way. I just don't know how to deal with it!

I think the best thing you can do is not look to her as your best friend.
Focus on your other friends and just treat your time with her as time with her. Don't put so much emphasis on it. If she is rubbing stuff in your face evidently she does not value your friendship as much as you do.

I think that is probably the best way to deal with it. I know that if I devote my full energy to her, I won't necessarily receive the same amount back. That frustrates me and I think I hold a lot of resentment towards her, which she doesn't even realise, or seems not to realise. I just want the bitterness to fade and start with a clear mind. I'm just finding that difficult.

Hi, I agree with what the others have said, I do not think that you should focus your time or energy concentrating on her, there are many people out their who are like that, and everyone comes into our lives for a reason, to teach us something.
Im not sure if you would agree with me, however, we see in others our own reflection.
Like the proverb goes:"The mirror was a useless invention, the best way to see our true reflection, is the eyes of someone else."
Basically what I am trying to say is, is their anyhting that you can learn from your friends behaviour, is their some reason she is their to teach you something, can you see yourself being anything like her in any other relationships.
What's funny is if we have to think about it, why do people like your friend worry us and our emotional state so much, so much more than we would lie it to.
There is obviously something deeper.

Hope this has helped you, and maybe you need to reflect back onto your life and take back the power you have given her.

Blessed be