What Causes Flu Symptoms, Stuffy Head, Runny Nose And Sore Throat?

Last week I was sick with what I would say was the flu, very exhausted, fever, extreme headache, heavyness in chest. that was all last week, this week it's gone to a cold. i have dry coughs that keep me up at night, stuffy head, runny nose, sore throat, fatigue. Is it something I should see a Dr for or just let the "cold" run it's course?