Rattling cough 27 weeks

Has anyone had a rattling cough in their chest that caused aggressive coughing for 2 days? I went a couple of days with this terrible cough and went to my drs appt yesterday where I was prescribed a z pak and cough syrup. My dr kinda freaked me out by telling me that if you cough forcefully you can actually break your water bag. Has this ever happened to anyone? My nurse said I would know if I had a slow leak as my underwear would have a clear fluid/liquid in them. Would I even be able to determine if this was amniotic fluid? I'm freaking out here!

Any advise?