[Symptoms] Fatigue, weakness [URI] Sometimes [Influenza] Very common, can last for weeks, extreme exhaustion early in course [Allergy] 
Sometimes
C o m m o n
V e r y c o m m o n
S o m e t i m e s ( p o s t n a s a l d r i p )
S o m e t i m e s
U n c o m m o n
N e v e r