Thanks for writing your query.
My advice to youwill be that you should immediately get her examined by a Paeditrician.
It seems that she needs nebulization with a bronchodilator
In addition to nasal congestion
, she seems to be having bronchoconstriction
which is causing cough
. Giving bronchodilators will help in relief from cough and wheezing. Give medications under medical supervision only after getting her medically examined. If any infection is detected, she will need proper antibiotic.
The reason for not able to continue breast feeding for long periods is that her nasal passage may be blocked by dried nasal secretions. Normal saline nasal drops will help to give her some relief.
Make her surrounding warm and ensure that she is properly clothed.
I hope this is helpful to you.