I got a cold about 6 days ago, just in the last 3 days i've had a low-grade fever, chills, body/headache, also very congested lungs. flu?

Viral illness: It's unusual for the flu to continue on for 6 days, however everyone's different and I wonder what your overall health condition is? Someone who has medical problems at the outset is more prone to a longer, more severe illness. The best thing to do is call your doctor and try to get seen for an evaluation. With a fever, the severity has increased. A proper diagnosis will help focus the treatment.