It's Subjective feeling of fever.
There are multiple causative factors for the same and Basic mechanism behind this is electrolyte imbalance (Sodium, Potassium, Chloride , etc..)
Electrolyte imbalance is due to any kinds of Viral or Bacterial infections, Stress,Sleep irregularities, and dehydration.
Next Steps
to get idea about root cause
get some basic tests done.
CBC with ESR
S.electrolyte
LFT
KFT
Consultation is advised
Health Tips
*Have Plenty of Fluids (Water,Fruit juice) to keep body Hydrated
*Protein rich diet
*do not stress yourself
*Monitor sleep quality
WISHING YOU HEALTHY RECOVERY