What Are the Flu 2019 Symptoms? Many of the symptoms of the flu overlap those of the common cold. But in general, the symptoms of the flu are much more severe. There are a number of symptoms associated with the illness, including a fever over 100.4 F, aching muscles, chills, headache, nasal congestion, sore throat, fatigue and sweats. The flu virus usually lasts around three to seven days. However, certain symptoms like weakness and ...