For this one you should check with your provider. The medication is generally safe and effective when used properly. But rarely there are some side effects which should be checked before another dose cycle is given. 

This is a tough one. It's hard to tell you next steps by this description but it sounds like you are a concerned and caring mother and you deserve some answers.  Many symptoms can be common in normal 5 month-olds but we have learned that a mothers concern should not be dismissed lightly. Our suggestion is to rely on your medical home, likely your pediatrician, to help coordinate any testing and care. There are always more tests to order and that's not always a good idea!  But if we had to guess the next stop would be a pulmonologist. They are the ones that deal with breathing problems and may suggest a sleep study. If he is really not breathing and dropping his saturation at night that seems to be more than reflux and a pulmonologist will know the next steps.  We will get one on a future chat.