A 6 day long fever and doctors cant tell why this fever?

I have had this fever for 6 days now, 3 days before it I got a swollen lymph node beside my right ear. The swelling is gone now, but the fever continues. One of the doctors I’ve went to (yes I went to 3 different doctors, since none knew why the fever) said that it could be because I have a slight pinkish color on the wall of my throat. But I dont see how thats related. I took the H1N1 test and tested negative, and a bacterial test but there was no bacteria or anything suspicious for that matter in my blood. Symptoms: A fever ranging from 38.7 - 37.3 (usually it gets worse at night) A headsplitting headache which usually only comes when I sleep, get up or sit down I.e. when there is a change of pressure in my head. I think it’s the usual headache everyone gets with a fever.

Every other symptom I haven’t mentioned means I don’t have it. I am taking Panadol (a medicine that decreases the fever and relieves from headache) once a day and it does help for 8 hours only. But why the fever? All my meals are home-prepared and I haven’t gone anywhere out of the house for the past 3 weeks (except to the doctors and a tailor). Doctors have ruled out mumps because my swollen lymph node didn’t hurt extremely but only slightly. ANYONE HAS ANY IDEA WHAT IS GOING ON?