How Can Fever And Sore Throat In An Infant Be Treated?

Hi, my son is 6 weeks old and has had a temp of 37.5 all week and been really off. I ve taken him to the doctor twice but they couldn t seem to find anything wrong. Just a slightly red throat (which could have possibly been from all the crying) he has had panadol once a day since Monday but today has had it 3 times (4hourly) and his temp is currently at 37.9 and hasn t come down since he s had panadol. I realise I shouldn t give panadol for more than 48 hours unless instructed by a doctor. Just wondering what you would suggest I do? He has no other accompanied symptoms other than the temp and being really unsettled. His nappies are softer and dark green but not loose. His immunisations have been postponed from this tues to next because of his temp. how long should I leave it before going back to the doctor? Thanks ​kelly