Can you think of anything that was different from your normal routine with the flu/cold symptoms started up?
These as well as cough, in my opinion, signal a chemical exposure
I would be especially concerned about 'the chills' as that is one of the signs of Autoimmune Hemolytic Anemia that exposure to 'the flu symptom causing chemical' would cause
http://www.valdezlink.com/generic.htm#8
Sweats might be start up of lymphoma ... sweating abnormally might be some type of autoimmune issue that affects the glands
BUTYL causes ME, CFIDS, CFS, FM 'gulf war syndrome'
http://www.valdezlink.com/re/butylcauses.htm
What we blame on a virus - for colds and for 'the flu'
is more probably a chemical exposure to BUTYL or EGBE