Have Fever, Stiff Neck, Pain From Neck To Skull Base. On Metronizadole For Possible Tooth Infection.

Hello. I wondered if you could help. I've had a temperature for about three weeks now, accompanied by a fairly stiff neck and a throbbing, shooting pain from my neck on the left hand side into the base of my skull, on the left hand side. The shooting pains happen about three times a minute. My head feels very heavy and I have a general feeling of tiredness and feeling unwell, a slightly dizzy, underwater feeling, with sensitivity to bright daylight and the light from my computer screen and smartphone. I thought it might be a tooth infection and I visited my dentist today, who told me that he doubts my symptoms were related to my tooth (which had a root canal treatment), but he's given me Metronidazole to take for 7 days to clear up any possible infection around that tooth, to see if it brings my fever down. I have a doctor's appointment, but I could only get one in 8 days time. The pain is really quite intense now and I would have sought help earlier, had I not been away on an acting job, that couldn't be interrupted, due to tight shooting schedules. Should I wait until my appointment with my GP on 24th May or go to the A&E department of my local hospital, if you think it might need immediate attention?