So my toddler was sick about two weeks ago: running nose, congestion, fever and coughing. I took him…

So my toddler was sick about two weeks ago: running nose, congestion, fever and coughing. I took him to the doctor and he was clear for strep, pneumonia, and croup so I was advised it was a basic cold and if it don't go away within two weeks bring him back. Well he still have the coughing at night but he been fine. Well now my 6 week old has congestion, sneezing and coughing. It just started recently and it seem like the coughing is getting worse. I tried everything I could do to keep them separated while the oldest was sick. Is there anyway I can help my newborn? I am taking him into the doctor in the morning to be checked but I'm just concerned and feel bad that he sick.