4 month old Cold and Cough

My lil one is seriously congested. I've done sitting in the bathroom with shower so she can breath the warm air... Vicks... But she won't eat. Since yesterday around 6. I've given her maybe an oz ... She will drink the pedialite but not the milks. Still has wet diapers and a few poos. I know my dr says they have to wait it out at this age but anything else I can do ???  Also at point do I call the dr because she won't eat.