Frustrated with my boss !

Alright so I work at a daycare and I totally understand I'm going to get sick blah blah. 
However there is this child who has a contagious skin disease. My boss was told about it when this child stared daycare and my boss passed it off as eczema. Meaning that they didn't look it what what it actually is /how it is passed/spread or transferred.
(Touching any of the sores, the child's clothes, playing in water/sand bins together etc.)
After finding out about this this morning I asked my boss if I should go get checked out considering you know baby.  My boss came back saying not to worry about it because the child's own mother is pregnant as well. ( eased my mind for a minute then I remembered she is MUCH further along than I am. I'm only 7w3d and have been exposed to this for plenty of weeks and my little babe right now is more likely to be harmed by diseases and such) then my boss goes on to say "Well I'm not worried about it, nothing we can do now anyways." And more about how kids always get sick n stuff  (Totally understand that too! We've already been exposed so what can we really do..)
But I said that I am a little worried and I never even got to finish my sentence before I'm interrupted by a "then I guess this isn't the right field of work for you." 
I didn't even bother to say anything I went off to play with another child. 
But just excuse me?! Who are you to say that to me? I'm not only taking care of myself but doing everything I can to support and take care of this child growing inside of me. I mean it might not seem like a big deal to my boss but they only have one person to worry about I have at least two!