I was in a very similiar boat at the end of year 11 - there are a few factors here.
The first one I think and one that alot of people dont mention, is to think about how realistic your goals that require chem are? and how realistic are they if you do chem?
By that I mean, if you want to get into a course that requires a 95+ atar, are you absolutely SMASHING your other subjects besides chem, going to continue killing them, and definitely be able to get at least a 25 in chemistry? You will have to be real with yourself and really think about it.
Secondly - how bad are you at chem? Do you really hate it, only want to do it as a pre-req, and are not good at it? if so really consider if you can definitely get the 25 and how it will affect both your happiness and grades.
For example, I did 1/2 chem and did really shit. I failed every sac and only passed the subject by doing redemption sacs that the teacher would literally tell us what the questions would be. Even then I struggled. The only reason I wanted to do chem was to do med, but then I realised a) i probably wont get the atar for med b) if i did i probably wont 25 chem and c) I dont even like chemistry and any course that requires it will fuck me. So i decided to drop it. you should have a similiar reflection.
If you really wanna study biomed/physio/health sciences and you enjoy chem but just got bad grades this year, then give it a crack, if not , think twice about it