3 weeks later post covid low grade fever

Hi 3 weeks post covid i had recently developed an elevated temperatures upto 99.5. the temperature usually come at 7pm to 12 am and become normal early morning and during day. I feel active throughout the day but when my temperature goes to 99 and above I start feel week. The temperature comes with slight infection in throat but whenever the infection subside, temperature becomes normal and I feel energetic again. I am also doing regular body exercises but it's been 16 days now and my body temperature varies from 97.6 to 99.4 in a day. My CRP reports and CBC reports are normal and under range except absolute lymphocyte count that is 3600. I am failing to understand this body temperature fluctuation per day. The fever do not cross 99.5 mark. Please suggest.