does your school not have applied science? which is coursework and you can improve on them, I believe many of my friends are doing it and they say it is fairly straightforward. A friend of mine wants to do radiology and she is doing applied science (i believe its called) it is really hard to choose but I would recommend sociology, because you haven't done gcse history. If bio is hard history is even harder in my perspective, but if u prefer remembering dates, doing essays and learning in depth then yes go for it. I feel bad because I don't personally know you so any advice I give won't be exact, so don't take anything to heart. good luck!