How dangerous is black mold?

I live in a trailer type house and one of the bathrooms has black mold on the wall. The mold was only discovered yesterday and I have been out of the house for the last week. But I have been dealing with a severe case of bronchitis which has sense gone away but been followed by severe shortness of breath for a little more than the last month. The shortness of breath has stayed with me even when not in this house. Is it possible this is all from the mold? And how dangerous is it to be in a different room in this house if that bathroom door is closed? is this a danger?