A sac is a small portion of VCE, and if everyone did crap on the sac then like your study score isn't damaged that much, maybe a little scrape but the main thing is staying consistent in your progress and reflect on what you could do differently.
For me when I get a crap mark I look at my test paper for an hour and analyse my thought process for each questions, then go on youtube or use a textbook or chatGPT or whatever has example questions and solutions, then compare my thought process to the example answers and see what I could think differently to improve my answers.
