Got the flu 3days ago&have had mostly fever&mild congestion.now getting a sore throat. always cold&weak. starting to worry, feeling worse, visit er?

Virus: It appears that your virus is working its way down to the throat and later the trachea(windpipe). This is not unusual for the flu and you're still in the viral stage. I would sit tight for now with tylenol (acetaminophen) unless there is worsening fever, shaking chills and heavy cough which could indicate a bacterial infection and probable need for an exam and antibiotics.