I have many many suggestions, so:
1. I HATED chemistry after year 12 - in fact, the only reason I did it at all was because, like you, I couldn't find anything to put into my degree. I decided to do it because everyone was telling me chem was a good idea - and I'm so glad I did it. Compared to (what I found to be) the horrible 3/4 curriculum, chemistry at Monash is not only excellently taught (Chris + Mary-Rose make the ultimate chemistry teaching team), but it is incredibly fun. Definitely consider doing chemistry, still. (also, my chem marks were not that good in year 12, despite what my degree/current marks reflect)
2. If you want to do third year physics, you HAVE to do the following three units:
MTH1030/MTH1040
MTH2010
MTH2032
AND second semester second year (to memory) has either a co-req of 2010, or it's highly recommended. So, if you think you'll continue into physics after first year (assuming you can't transfer over), do those units. Note, MTH2010 is not hard to score well in if you do it this year - think of it like doing methods again, but without the fucked up questions.
Conversely, physics is incredibly hard to do well in, so you might want to consider doing another set of units over them.
3. At this point, you've played your hand in all the three main areas of science - but not much else. Why not try something different, such as ASP1011/ASP1022 (astronomy), or ESC1011/ESC1022 (geoscience). Both combinations aren't too hard to do well in as long as you put in the effort, although I think most people say ASP1011/1022 are easier than ESC1011/1022.
4. You don't HAVE to do all science units. If you can't find something else from science to put in, but like analysing literature/films, why not take up an arts unit on literature or film studies?