Hi. I Am A Healthy Active 65 Year Old Woman

Hi. I am a healthy active 65 year old woman in good health. Had a complete physical in November. For the past week I have been having a low grade fever that starts in the evening. It has never been over 100. I feel achy. I think some glands under my chin get swollen. If I take a Tylenol all symptoms go away fairly quickly. Even if I take no meds I am better by morning (although I don't sleep well.). I feel fine all day. Good energy, no fever, no swollen glands, good appetite. Tonight is my 8th evening in a row with the same symptoms. What should I do next?