A Level Choices?Watch
Since you're so undecided, I would suggest trying to take a broad range of facilitating subjects, so that you'll be eligible to apply for a variety of different university courses. For each of the careers you're considering, do a bit of research into possible ways to get there (including specific degrees). UCAS might be a good place to start your research. See which A-Levels are required for each course you're considering, then where there's overlap you can see where some good options might be.
As sidenotes, I would be wary of doing all essay subjects, as you're likely to get a lot of work for them. On another note, having done A Level physics, I disagree that maths is necessary to do it. Sure, there are a few new concepts beyond GCSE but they're not too difficult to get your head around and they're explained in the textbooks (or by your physics teacher!). That said, physics courses at university will require A Level maths so bear that in mind.
Best of luck with your GCSEs!