I went by myself last year, it's not that big a deal. I had plenty of male friends who knew ahead of time that I didn't have a date so they promised to save me a dance, it depends on your friends on how many of those promises are actually followed through on. And I was with my three best friends who were kind enough to allow me to "borrow" their dates for a dance as well. It's actually not bad, and I had a great time at my prom last year. This year I'm going with a good friend from the math team, so we'll see how that works. Relax and enjoy your prom, you'll be paying quite a bit for it so have a good time, you'll remember it good or bad so it's better to make good memories with your friends.