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You need to get treated for the headache;dizziness;fever which you have presently.It is important to see what sort of fever whether viral;malarial;typhoid
and then get treated accordingly.If you have viral fever
then the dizziness can be due to weakness or anaemia
.As for the hair fall
normally you lose anywhere from 20 -30 hairs daily which is normal and even fevers can cause increase in the hairloss.So first get treated for the fever and hopefully the hairfall will stop.