Natalie, I really do wish I could offer some advice or something but the only thing that comes to mind is that you have adhesions or adhesions with the SC which is what is causing all this pain and stuff. You have another 9 days to go to see Mr Porter. But I do suggest that you phone his secretary tomorrow and check a) that he is going to be there and b) that you are scheduled to see him and not his registrar.
Another thing you could do is start making a diary of all these happenings, day, time, what happened, your pain score, what meds you took, how effective they were, etc., etc. Make the list in bullet points by date and time rather than an essay. Highlight some of the more extreme experiences in red.
Send it to him a couple of days before the appointment. Mention this to the secretary when you speak to her, perhaps she will be kind enough to give you her email address for convenience. Also take a copy with you just in case her doesn't have it to hand when you see him.