You're not ugly Sadie. You're fucking beautiful. You're only 13 you don't need a boyfriend at your age. I worried about that at your age but it didn't really matter. You just haven't met the right person yet. Besides by the way you talk about people in your school you wouldn't want to date any of them.
The best thing to do is avoid relationships until you're out of school. It means you don't have any silly high school drama to spoil anything. You're beautiful Sadie, you don't need a boyfriend to prove that.