I have had a respiratory ailment for a week. most symptoms are gone except a cough, fever that returns at night, lethargy. when is this going away?!

Duration of cold?: Usually the recovery from an upper respiratory viral infection will take from 1-3 weeks depending on the virus, its virulence and the underlying constitution of the individual. Most folks recover in 10- 15 days. The persistent fever could indicate a deeper problem. You may want to address that with a doctor.

See your family doc: Respiratory ailments that persist, and especially if associated with a fever may be sign of a "walking pneumonia". See your physician.