I feel sick when i look in the mirror, and i'm pretty sure that people feel sick when they look at me.?

I'm a 15 year old girl and every night i go to sleep i hope that i will not wake up. I hate my life, i hate my personality, i hate my appearance and i hate my personality. I've been this way, on and off, for about 2 years. I'm writing this because i feel like i can't talk to anyone about it. I have one friend, well i had two, but long story short, we argued and now she seems set on telling me all my flaws and things that people dislike about me. I know those flaws are there, i just hate being reminded, which is a kind of regular thing lately. This gives me more incentive to grab a box of tablets from the shelf, which i've been longing to do for a vast amount of time, and end it all. I used to be tolerate myself; appearance wise, but now i physically feel sick when i catch a glimpse of my face. The right side of my face is exceedingly uglier than my already atrocious left side of my face, so i try to turn so they don't see my right side, making me look more awkward than i already am. My mum told me that we had to go and get my pport photo taken so i began to cry hysterically. I've had one boyfriend and a boy likes me as we speak, but they get made fun of for liking me, that's why i get so confused. Not because i am unsure whether i'm unattractive or not, because believe me, i am. I am the runt of the family, my sister is masturbated (ew) over by every teenage boy in my school, including the boy who currently likes me and my little sister is constantly stopped in the street and told that she is beautiful. I, on the other hand, am proof that books are judged by their cover, well... What's inside is sh** too. I am so desperate for people to like me that i make jokes which then eventually end up sounding nasty and cause people to talk about me. ANYTHING upsets me. I'm a vegetarian and when i talk about my views i seem like a preachy, unrelatable, crazy freak. So i shouldn't bring it up, but what else do i have to talk about? I'm dull and boring unless i'm using offensive jokes or spreading gossip. What a f****** idiot. The only thing i have going for me is my intelligence, which people would obviously resent. I talk "properly", so sound like a stuck up tw**. My "friend" is right, i'm easy to hate. Even my own brother calls me a loner, it's true, so i can't be mad at him. I haven't gone out for months and i dread school days. I am crap at my makeup and hair, it's always the same and i have NEVER worn a skirt. So what the hell will i do when it comes to prom? Or my 16th birthday? I'm scared that if i wore one i'd look like mutton dressed as lamb and i's be even more laughable. I want to change, but i don't know if people will let me. I can't wait to move school when i go to sixth form, but even then i'm awkward in social situations (I am called a social outcast) and i more than likely wont make any friends there either. Why was i born? Will i look back on this and be like "so?"? Help me please.