A level choices- how hard would this be?Watch
For medicine, unis will want to see chemistry and biology for certain, and possibly maths - anything else is up to you. Personally I love physics, but if you're only taking it because it looks good and you don't really like it then it may not be the best choice; it shows logical thinking and some of the medical physics you learn in the end of the course would be useful, but it's not essential.
Judging by your GCSE results, you're pretty smart, so I'd say take them all and see how you do / which ones you are better at.
Is the Bac compulsory for you?