Ahahah cheers man, though I know kids who are nailing like two past papers a night!
Dw man, I do all humanities too except 2U and 3U math! It's definitely not too late to learn your content, you've got 32 days left till HSC starts. I find that I learn the content best through doing, so maybe aim at doing an essay every two days. Supplement that with dedicating 30 minutes to an hour each night just reading over your notes, until you know the content inside out.
From there you can start doing past papers! If I was in your position I'd aim to have complete knowledge of the content by Monday the 21st, so you can spend three solid weeks doing past papers so nothing trips you up. With humanities past papers you'll find that they can only ask the question so many different ways anyway!
Not too long till its all over mate, we're all gonna make it ahahahah.