Think about this..
1. We're all connected someway. If you think about it, eventually you realize that some person you know may know another person and another. It NEVER ends.
2. We are all created by the same ****. Atoms/molecules/DNA/elements...
3. That girl you shake when you see is no better than the other unattractive girls at your school. The only reason she is is because guys you like make her believe she is.
4. She ****s bombs just like you. She probably has nasty habits like you do.
5. Based on the Declaration of Independence, "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness."
Think about that; we are ALL CREATED EQUAL. You are depriving yourself of equality.
What you need to do is begin to treat everyone the same. Treat the unattractive girls like you do the attractive. Same goes for popular or unpopular guys. Even the people you hate you. Once you can view everyone as equals, you will never have this problem. Your perception of others is skewed by your attachment to physical beauty. Consider the part of her body you love most. For example, there's this one girl i know, has huge/round/toned calves/thighs/ass/body. She's toned all over and i'm gaming to get some ass action before i graduate, which i'm pretty sure i will. ANYWAYS, how i think about it is this. Those sexy legs of hers are actually just comprised of skin (made of protein) and the blood, nerves, Lymphatic system, respiratory system, etc. What you're seeing is actually just a bunch of basic elements being pieced together.
You might as well buy a blow up doll that fits your ideal shape and **** it. I understand your problem but Go Deeper. (Heh, that's what she said)