Hunny I am sure that your baby will be ok.
As long as you try and stay away from the mould now you should be fine too.
Go to your GP just to be sure though, I am not a Doctor but I have an allergy to mould.

Has your Landlord got someone to come and fix the problem?
They need to action any resonable request within 7 days I think. Google Tenants Rights to find out what you can expect and ask for in your state.