Hello Doctor! I Have Been Suffering From Internal Fever For

Hello doctor! I have been suffering from internal fever for past 1 month but the thermometer does not read the temperature. Earlier it used to be regular but now it comes after 3 to 4 days. Basically I feel the fever in my throat, neck, eyes and tongue which gradually spreads later on. Initially the temperature read by the thermometer used to be 99.5 or 99.7 but now it is like 98.1 or something. Many doctors have told me that this not fever but from inside I feel temperature. I have done reports of malaria, typhoid and all but all the reports were negative. I would be really grateful to you if you could help me with an answer. Thank you.