I have had probably the worst 5 months ever, I was someone who had a small bout of health anxiety when I was 16 but it cleared up pretty quickly after, I hadn't been to the doctors in years and am only 25. One night I woke up in the middle of the night feeling like my face was going numb, heart racing, vision felt off, went to ER, everything clear. As the month went on I lost weight, and had a mild fever of around 99-100, twitching, vision issues, but then there's the fever, It was always normal when I wake up and gets up to around 99.3 average, and highest is 100. But this happens EVERY DAY, and has happened for 5months so far. I have been to a neurologist, endocrinologist (since my thyroid was slightly hyperthyroid) everything clear, been to an ENT, and also had a heart echo done, multiple brain MRIs, Neck/Head CT, Thyroid Scan, Lymph Node scan,  so much done in the past 5months. And while my symptoms come and go and change, the one consistent thing is (anxiety) but also this mild fever, and while I can kind of ignore the other symptoms or they go away and come back, the fever is the quantifiable thing that I can't ignore, even if I still feel "Ok" I look and still have of fever of 99.6 etc, I have taken it with an oral and temple thermometer and its always the same. Doctors don't seem to really focus on it, but it's driving me crazy thinking I have some underlying cancer or bad condition that's causing this fever for so long. I don't get chills with it or aches or anything ,its just a constant mild fever that tends to go with the flow of the day (98.0 in morning, 99.9 by evening". And no I have never had covid  to my knowledge and tested myself for it a lot, and am vaccinated as well.