Go to A&E, at least you'll get things moving on the system, be "assessed", and speed up the possibility of a quick MRI scan.
A&E is Accident & Emergency. Have you had an accident or is it an Emergency? If not, see your doc. I have a mate who is a triage nurse and she says that about 60% of people shipping up at A&E with a sore knee, headache, bumped elbow etc, could have just gone to see their doctors. She says its a PITA when people do that (she is equally peed off with people using A&E when they have a cold or a hangover).
See your doc for advice and if you are not happy with it, ask for a referral. Just had a doctors referral myself - dodgy wrist - and he has got things moving along for me nicely. Seeing the specialist the week after next.