High body temperature. Fasting is 98.

For the past around 15 days, my body temeperarure stays on the higher side. In the early morning it is 97.6 to 97.8 and as the day progress, it goes to 98.3 or 98.5. If I am working somewhere like in kitchen or do anything, sometimes temperature goes to 99.2 to 99.6. No cold, no cough and no body aches. I got few tests done today where Widal was negative. TSH is 6.8 for which I am already taking Thyroxin 50mg. Urine test is normal. Blood platelet is 141. Lymphocytes is 40.7.Hemoglobin is 15. ESR is 4. T3 and T4 are normal. Total cholestrol is 203. LDL Cholestrol is 141 and Non HDL is 159. I feel bit exhausted when temperature goes to 99. I do not take any medicine. If I rest for 10 to 15 minutes, it automatically comes down to 98.4 or 98.5. Please suggest if there is something to be considered. Sugar fasting is 98.