Help, are our belongings okay, or do we need to throw them out?!!!

We are currently renting a house in Germany and will be moving out (coincidentally) in a few weeks to a newer house but we have JUST realized there is black mold in the basement – probably everywhere!!! We had A LOT of boxes still filled with things since we just moved here a few months ago. We also had some furniture in those rooms. We don’t know how bad the situation is yet. However, we can see it coming through the walls and there is black on the boxes. My question is how safe is this, are the things that were in the boxes ok? We have already re-packed them and moved them out but I am so nervous. We have two small kids and I have been sick but not sure if it’s related. It has smelled musty since the day we moved in and the walls have been somewhat falling apart down there but we had NO CLUE!!!! HELP!!!!