2 things you have to realize is that:
1- Life goes on after High School, I know it seems like thats all that matters right now but you move on and you go to Seminary, College, Work… you make new friends and you have a whole life in front of you, with new friends and new opportunities.
2- When you are in High School everyone is trying to find out who they are, once you leave thats when you REALLY figure these things out. Girls who were your best friends then can totally change and girls who you thought you had nothing in common with can become your biggest support.
Just keep an open mind, its not the end of the world if you dont have a BEST friend, remember its only one year and then your on to bigger and better.