My self cofindence has gone?

I used to be really confident through out primary school, i used to do as many activities as i can with people, speak to everyone without worrying what to say. But ever since my brother died, i feel all my confidence has gone completely, not just because he has died but he used to praise me, tell me how good i was, we had a very strong bond, i still find it very hard to imagine i'm never going to see him again. Also my best friend, she had literally no confidence what so ever! So i used to boost her up all the time, now she has more confidence than me, she has a perfect boyfriend, and way more friends than what i do! I'm not blaming her but i also feel all my confidence has been given to her, now she over shadows me. So socially i'm scared of opening up, speaking my opinion, standing up for myself, so pretty much getting out of my shell. I am scared of speaking to people, sometimes i feel i have to tell lies so they would want to have interest in me, because i feel if i just be myself than i'm going to be boring. Because of this, i tend to only speak to people that i feel comfortable with, or people that i don't know who doesn't know me, so i don't have to be the person i am at high school. It's really weird because you wouldn't think i do drama, i absolutely love acting, and when i'm acting i suddenly do get this rush of confidence, i think it's because i don't have to be me, i'm pretending to be someone else. Also sometimes when i look at myself i think i do look pretty, i buy the nicest clothes and do my makeup nicely. But other times i feel so disgusting, i pick out all my imperfections reminding myself that's why that boy doesn't like you..I know i'm only 15 but i haven't had a proper boyfriend, so haven't really kissed anyone. Even though i'm told im pretty, and that i could be a model, i just feel if i had a boyfriend than maybe i can start believing this complements.. I could go on further more, but this is a quick sum up on how I feel, i don't know whether this is an issue for me to see someone, or if there's anyway i could boost up my cofindence by myself? please help many thanks!!!