Bergs - call 999 and say or make up some 'tripped over the cat' story. I know from experience (and Sue working in the NHS) that if you call 111 it's automatically treated as non-urgent, and you follow a different treatment protocol.
To back this up. When I had life-threatening Covid, I was discharged the following day with a doctor prescribing rest. The day after that Sue took me back in at Death's door and I was in ICU for 10 days!!
Years ago, my Dad couldn't pee due to prostate enlargement. My mother wanted to call the local doc at 2.00am. I got up, saw how much pain he was in, and called 999. Later, the local GP said that if my mother had waited for a local doc, his bladder could have ruptured, caused sepsis and possible curtains for him.
Focus on doing anything to get into hospital mate. Once you're there, they have to investigate, and you know you're in the best place to sort your back.
TBH, the NHS needs to get back to basics as it's currently broken. Focus on emergency and critical care only, with everything else either pay as you go or insurance based. It'll take time getting it right, but proper health care from cradle to grave with the current set up is simply NOT possible.
I'll just add that my treatment for Covid at my local hospital was, in the main, excellent - despite it being rated as one of the worst in the country.
Ring 999 NOW mate - you are in an emergency situation!