#5 Continous fever
Just having a high fever is not the only sign that you should get in touch with your doctor. Maybe your fever is not that high, but you keep on having one. Persistent low-grade fevers are never a good sign, especially if they have been going on for a few days. Not only is this going to leave you feeling bad for days on end, but it is also a sign that your immune system is fighting against something more than just a simple cold.
Other illnesses like mono or the flu can cause your body to react in such a way, so even if it does not seem like a big deal, you should definitely end up checking it with a professional if it’s been a few days and you cannot shake off the fever.