Being ranked fairly high is fine (provided your cohort does well) - it's more than possible from here you'll get an ATAR above 85 (might be easier/harder depending on other circumstances which I'm unaware of). The best thing you can do is help out your mates and push yourself to do the best you can from here on out - don't worry too much about something you can't change, try to use it as a baseline for improvement
An important thing to note is that Trials are generally harder than the HSC for a multitude of reasons (identifying areas of improvement, generating a greater spread of marks for ranking reasons, etc.). As an example, I got 77/100 for my Physics Trial and 80 odd out of 100 for my Chemistry Trial, if I recall correctly. Those exams were much harder - so expect yourself to potentially get a small uptick (but don't bank on it because this will 100% cause complacency). To really get a significant buff to your marks, look to target questions that you got wrong. Try similar questions, change the numbers, revise the theory, change the wording of the question, reuse the question for a different syllabus point - stuff like this will always help. Don't leave areas of strength behind either, because you need to get guaranteed marks and confidence from somewhere as well. Exam-style questions are really the best way of doing things - your teachers may have resource repositories you can pinch stuff from.
Make sure you relax as well! Going through tough sets of circumstances (mental health, mental overload, family trouble, misadventure, physical illness) won't do you any favours, and it's important to remedy these things where possible before doing any hard grinding. These things are tough to work on and oftentimes have no definitive solution, so you'll have to creatively manage these things or be lucky enough to be relatively unaffected. In short, try to keep yourself as healthy as possible