Literature is compulsory for all lower secondary students.
You can't drop humanities, it's one of the required subjects to
gain entry into a JC, CI and Poly.
Physics will not be difficult if you like it. Same goes for
Chemistry and Biology. But I've to say Pure Bio maybe too hard for
some students, as it can be quite detailed and a lot of big big
terms to remember. You might like F&N instead of Bio.
If you took combined science for your O Levels, it will be harder
for you in JC. You have to study doubly hard because a lot of
things are covered in pure science and not in combined science.
It's recommended if you wish to go JC, do some reading up before
school starts. This will lessen your stress.
Social Studies is not offered in lower secondary, it's a compulsory
subject from upper secondary onwards, so you will only touch Social
Studies once you are in Sec 3. First few chapters of Social Studies
should be easy if you remember your Sec 2 history facts well.
As for Geography, I only can say that Geography Elective is easy
because it's mostly common sense. It's even better if you read the
newspapers a lot, especially those about manufacturing and farming.
I'm not too sure for Pure Geography, I never took it.