Assuming that you have been thoroughly preparing for your HSC exams prior to the HSC exam period, you should adopt a "control" approach throughout the time that separates you from your next exam. This means that you should capitalise on the opportunity to further supplement your preparations in the next 6-7 days, while ensuring that you do not overwhelm yourself as you mentioned.
Given that this is a significant time period, you may wish to have a break and not study for the rest of tomorrow after you complete your English Advanced Paper 2 (best of luck!
). This is something that you can treat as a small reward/celebration for the fact that tomorrow will mark the end of your HSC English journey, which is a huge milestone without a doubt. The following day is when you can then get back to your preparations, which is where the notion of control becomes relevant. Mathematics Extension 2 is definitely a challenge and the time that you have prior to this subject's HSC exam is precious. You should therefore make reasonable use of that time in the sense that it will allow you to revisit concepts that you may not be fully comfortable with as well as maximise your practice, consequently preparing you more for the exam.
I hope this helps!