New job and sick baby

I just got a new job. I also have a 5 month old who’s in day care and gets sick all the time. The job is a 9-5 office job. I don’t want to make a bad impression at the new job, but am not sure what to do when baby needs to stay home from day care when they’re sick. Looking for advice on how to handle this and just general support on not feeling worried about needing to take frequent sick days. Full disclosure: I haven’t told anyone in the hiring process that I am a new mother to a 5 month old.