Thank you for your query on Healthcare Magic.
Loss of weight, nodes on back of neck needs further evaluation to look for any chronic infection such as tuberculosis
Investigations like sedimentation rate, chest x ray, mantoux test
has to be done to rule out tuberculous infection.Biopsy
has to be done on the enlarging lymph node for histopathological examination to know the nature of swelling.Bone marrow
study may be required if the counts are low.
Therefore I suggest you to consult physician for physical examination and for further investigations.
Hope I have answered your query.