Help please

Sarah

My 6 weeks old has had a cough for few weeks (docs tell me it’s nothing) but yesterday he was off his milk his chest sounds rattley and his nose is blocked can a new born get a chest infection? He is being sick after every feed with his coughing I didn’t sleep at wink last night cuz I was scared incase he choked. I am going to the docs again today with him just wanted to ask on here 1st