Hi,
You should get in investigated. It's important to know about the duration of illness to guide regarding its probable cause and management.
I will suggest you to get few tests like
complete blood count and peripheral smear, ESR, blood culture, malaria antigen test, Mantoux test, Chest X-RAY. You may also require FNAC of lymph nodes.
General advice would be to take plenty of oral fluids, Tab Paracetamol in case of fever.
Hope you get well soon.
Best wishes