lol! if i get discouraged that easily, how do u expect me to do the HSC? =) i'll do my best if i'm bothered to study =) first thing's first, i'm more worried about school trials >.>
Don't worry about it! Do your best and if you don't get as high as you expected, then just relax.
I'll tell you about my situation.
I just did the SC Maths Trials at my school and didn't do as well as most of my classmates who got like 90+ or 95+ (I got 80 on the dot and yes, I expected 90+). And most of the time, I get at least 90+ (rarely 80+ or 85+) for my topic tests (even harder ones such as Circle Geo, Logarithms or Polynomials) and common tests for Level 10.3 Maths content which is meant to be harder! The levels of HSC mathematics (Gen, Adv, ext 1 or 2) should be decided with your 10.1,10.2 or 10.3 content rather than the SC exams.
Remember SC trials and exams DO NOT determine everything! I know people who got like Band 4 in SC Maths and start dominating in Maths Ext 1 for year 11 and 12.
And this applies for every single subject! For example, just because you didn't get a Band 6 for SC History, doesn't mean you shouldn't choose history (assuming it's your favourite subject). Everyone has bad test days and you can't just use one test to determine everything!
So overall, do not worry about SC trials and the SC itself and ALL THAT MATTERS is the finish line which is the HSC!