So you're single. That doesn't mean the world comes to a complete end. You should always look your best even if you don't have a man. You may not find one guy that can come close to being a boyfriend, but that doesn't mean you should stop wearing cute clothes. Try it! One day next week put on make-up, fix your hair, don't dress like you feel. If you're feeling bad, the worst thing you can do is wear clothes to describe your mood. Wear something cute, something that says I don't need a man to notice me to define my beauty.
I'm sure you're a pretty girl, but no one will notice it if you're looking down. Seriously, how many of us would buy a flower that's facing downward? The same goes for you. Take baby steps if you're not confident yet. Wear pretty lip gloss, or fancy nail polish, just don't give up on yourself. Never think for a second that you're not pretty because you really are!
You may need to clean your own mirror to see your beauty. For heaven sake please don't compare your looks to another girl's beauty. You're beautiful too, if only you knew. Stop wasting time complaining about what you don't like, because that's the worst thing you can do. Smile while you still have teeth, and fix your hair before it falls out when you get old. Live your life and make it the best!