Having daily low fever due to what.

Since 2 mnths temp varies from 97.6 to 99.8 ,earlier it is normal ,I'm 24 yrs male ,first widal done o& h titres 1:40 temperature varies between 98 to 99.8 after 5 days widal o&h 1:160 ah,bh 1:20, taken antiboitics like gudcef ,ornio, azithromycin, moxinow, doxt-xl,for 14 days,widal o&h 1:40 but fever pattern is same,morning after 9am increases to 99 ,after noon goes to 99.4 sometimes 99.8 night  comes to normal,10 days again went to doctor,blood tests smear for mp negative,chest x ray normal,us abdomen normal, mantoux negative,CRP 6,ESR 10 ,earlier 2 mnth back it is 26 now it is 10,scrub thypus negative,RF assay negative, thyroid normal,blood culture negative, thypoid igg igm negative, antioiotics stopped 1 mnth back,what is the reason for this fever,visted 5 doctors(md gen med)saying that it is normal no need to worry due to tension or stress some harmones are released, mine appetite is good , having headache,sir i want suggestion,fever continuing from 2 mnths isit tyhpoid