okay so i have failed my first HHD SAC, Got 16.5/20 for my english speech, 12/24 and 11/24 for my biology pracs and 81%,84%,81% for maths
should i be worried about my scores?
:/
If you feel your scores are lacking and that you should be worried, that's you triggering an internal wake up alarm

You've gotten your first taste of SAC's, the feeling of failure, and dissatisfaction. I'd been in your exact position last year, but instead of acting upon it, I was lazy, unmotivated and gave up. The cost. I got a very very low score for Physics and I'm repeating English, when my other friends are doing year 12 without the burden of the single most important subject (for most) for their ATAR.
Remember that your SAC Graded Assessments are compiled from all your SAC's for the Unit, so getting a low score in one SAC, doesn't necessarily rob your opportunity of getting a good SS. It merely gives you less breathing space, or margin for error in the rest of your SAC's.
I got 16.5/20 for business. A+ cut off last year was 93/100. Losing close to 4 marks on my first SAC just leaves with less breathing space for errors in my next SAC's. A+ is still well and truly possible. Harder, but still possible

Use what has happened recently as fuel for motivation

I'm sure you'll be fine!