you don't need maths, the only A levels you need are chemistry and biology, which you got. I would say don't even take maths as you yourself find it difficult, so an A in English will look so much better than a C in maths.
Also, English and modern history are very contrasting to the science subjects, showing to unis you are a well-rounded person, with histroy also giving you some analytical skills are are very important towards a medicine degree. bear in mind that, work experience is far more valuable than an A level in maths in my opinion. so if you don't want to do maths, don't take it, don't pressurise yourself in the extra workload trying to figure out how to do differentiation late in the night. your options are fine, in fact they're great! (but to be honest, I would do combined english or english lit, as medicine is very competitive to get in to)
good luck at sixth form, and remember to get some work experience!