Work injury and employee rights?

I was injured at work a month ago and it was quite serious. (Icu for four days) and my own doctor has stated that I am not fit to return to work, however the company doctor is being very forceful in his opinion that the injuries were minor and that I am perfectly healthy despite me telling him that I feel awful, he is also very rude and foceful saying that the specialists that I saw were making a fuss over nothing. Can anyone tell me if I have to continue with the company doctor or if I am free to solely use my own GP. Any other information would be greatly appreciated