I need help! My little boy is sick and?

Congested really bad. I just bought a humidifier. The other day I asked and people told me to buy a vaporizer, or a cool mist humidifier. I called my Dr and shouldn't use the vaporizer because of the medicine and Im pregnant. When I went to buy the humidifier, the warm mist one said it was for cold and flu symptoms. I bought the cool mist one because that's what everyone one here said, but my husband thinks I should have got the warm one... So, what should I do? Its winter here... Is a cool one better? Why?