I would have gone to the ER by now if I couldn't see my regular doctor due to christmas, a headache is one thing especially if you get them often due to stress or something , but a headache for four days as well as deafness in one ear would concern me. But then again the NHS is taxpayer funded, so the most I would have to pay would be a bit less than ten pound for a prescription if I needed antibiotics. Could be anything from a severe migraine, an ear infection, a virus, a tumor , blood clot on the brain, you won't know until you go. No point looking shyt up on the internet for most things.