No, do not drop out. I am in YR 12 as well and know how hard it is. Many of my friends were debating not going through with YR 13, but think about it this way - you will never get the opportunity again. Do YR 13 and get those qualifications, they're not meant to be exciting and fun, they are boring, but they will add so much more to your CV and I doubt that you'll ever regret staying whereas you probably would regret leaving.