3wk old temperature

Our family is currently going through a bout of sickness with my SO confirmed for two strains of the flu 😷 our bub is 3wks old and has just returned a temp of 99.2. We were told to rush her straight to hospital at 99.5 (under arm) so the paranoid mom in me is fretting. Her temp was fine this morning, but she has slept all day and taken very little when I've woken her to feed, however has been pretty alert for the past hour and took 100ml then (EBF) which is what she will usually have in a feed. My thought is to set alarms and monitor her overnight, or should I just take her in to be on the safe side?