Temperature 99.1

Candie

Baby boy is 12 days old and has been running a temperature of 99.1-99.4 degrees F for the past two days. Not really much out of character other than maybe a bit more fussy after feedings until tonight he vomited about 6 oz after feeding but may have overate???? Google and pediatrician say 100.4 signifies fever in newborn. Should I be concerned???