heya dude
im expecting to fail just like you, and i suppose all of those ppl that are telling to go kill urself are proberly nerds or really really smart people as they seem to congregate around here.
If you fail the HSC, then u fail the HSC. No biggie. There is a life after school you know, and it doesnt nessassary have anything to do with what you get at the end of year 12.
If ur concerned, think about the school certificate, and all the hype that was generated around that time with all the doom warnings about failing and ruining your life. Do you remeber that now? No. People are just like, meh, SC, who cares.
Thats what the HSC will be after you complete it.
Passed.
There are alot of future options available for you, and if you know your not going to do as well as everyone else, start looking for something to do now.
As you already mentioned tafe is good.
But whats better is an apprenteship (however you spell it).
Alot of skill workers are in demand now, such as electricians and such.