Sunday Morning Around 2:45, I Awoke With A Fever Of

Sunday morning around 2:45, I awoke with a fever of 101. It broke late Monday morning. In the afternoon I took my temperature and it was 98.6. Later Monday evening my fever returned to 101.5. Tuesday morning the fever was gone and regular in the afternoon. Now, tonight it has returned to 101.3. I am 48 years old an have never in adulthood had recurring fevers consecutive days. Any idea what this could be? My stomach and bowels are functioning fine. I am stuffy in the nose and have a slight sore throat. Thank you!
P.s. I am a teacher and work with kids.