When is your CPN seeing you next? I think she is on leave atm?
Have you been offered anything other than painkiller to manage your pain?
Is there a way to work part time rather than fulltime?
I know money plays into it, but maybe you can discuss with your parents if they can support you for a bit because, quite frankly, it is very obvious that you can't continue to work so many hours for the time being.
I think that despite the hassle and effort you need to look into getting disability another time. I understand it is very demanding and hard to jump through their hoops and fight what you clearly need to just live. But is it really worse and scarier than the thought of continuing the way things are right now?