Persistent low grade fever

My 2 year old has been experiencing a persistent low fever (never dropping below 100 and often rising to 100.5-101 and higher) for about a week and a half. He first started with symptoms of a cold, sore throat, croupy cough, runny nose. After his fever did not go away the dr. said he probably had sinusitis and treated him with an antibiotic. He has been on that for 4 days and the fever is not gone however his cold symptoms are. Should we still be concerned about the fever?

[Farmer4]

I have four children & in 2 of my kiddos when they get sick, the fevers do persist.  One child had a low grade fever like you are explaining for over 7 days, with higher fevers the first couple.  I also had one child that would run fevers when ever she was teething.  Sometimes going on 10 day runs of those low grade fevers before a tooth would pop through.  I would watch for signs of dehydration, but otherwise not be overly concernce for now.  Good Luck!