How can I build confidence?

There are times when I feel beautiful. But there are also times when I feel ugly. Also, there are times when I feel worth it or worthless. This whole cycle is driving me insane. I tell myself the beauty is a lie. Mainly, it’s because ugly beats it. Like always, we focus on the bad things and think they are more important than beauty. How do I keep myself from hurting? How can I accept who I am? How can I accept how I look like? I hate it when I look into the mirror and find ugly starring back. Especially when it reflects on my personality. I become self conscious, which turns to no self confidence. I’m just becoming weaker and weaker! My personality gets weak because I feel scared to show who I am. To new people I meet in high school, I no longer feel “safe” in showing who I am. I’m only comfortable around old friends. I always feel like there is something missing. I think that this is part of it. I wish you guys could read my mind. This might just be part of it.