Firstly although knowing your HSC content early is beneficial in the long run, I don’t know who told you that you have to have learnt the content by term 1 but they’ve clearly pressurised you. I can confirm it’s fine to not know all of your HSC content by Term 1, and is only optional for those who want to go ahead in their spare time after school.
Can’t really give you tips on economics because I don’t do it (and I hate essays as well lol) but with chemistry I can give a couple of tips. For something like chemistry which can be content heavy I’d constantly revise the course as a whole, also focusing on your weak points. With constant revision, information will generally move to your long term memory so by the HSC you should know your content back to front. Also in terms of calculation problems in Chem, similar to maths you should jot down the ones you can’t fully answer and either attempt them at a later time (not too much later!) or seek help from teachers. Last tip from me is to not disregard practicals, as they are tested in the HSC. Therefore every day when you go home after you’ve done a prac at school, you should probably write about this prac without any assistance of notes and try and remember as much as you can (e.g. apparatus, steps, validity, reliability), I guess it’s a way to revise your pracs and to test your memory to see how much you know. With what you don’t know from your prac, then I’d use notes for assistance. Main point: write about the pracs you’ve done in general as it’s important and could be tested!
Hope this helps and good luck, I’m sure you’re doing great
PS: Why are you up at 3:51am lmao