Hi,
H2 Chemistry is the most important. For medicine, either Bio or Phy
works fine in terms of getting into uni (for NUS). But in my
personal opinion, and based on what we are being taught, Bio will
definitely be more useful. Overseas Unis may require Bio or Phy
specifically (mostly Bio).
Bio at H2 level is definitely content-heavy. You will do well if
you have a passion for it. If not, it will be alot of memory work.
Physics requires alot of understanding, application and practise,
just like maths.
With regards to readjusting to a new class, definitely it will be
something to face. But consider that the subject you choose will
live with you for 2 years, while this readjustment is just a
one-off.
Talk to your seniors, especially if anyone is taking both, though
highly unlikely.
Reconsider H3 Pharm Chem. The whole syllabus is extremely tough and
lectures are nonsensical, probably worse than the physics you are
getting now. But I guess it may be better in your year, since my
year was the first and no one was really clear what was going in.
If you can, though, NUS Bio is a more viable and enjoyable option,
plus you can get it over and done with in 4-5 months, rather than
1.5 years for the MOE syllabus, and that the exam does not come
with the A levels, leaving you free to concentrate on your H2
subjects.
All the best with J1 =)