Hello Susannah,
It is possible that her teething is part of the problem for her congestion especially since she is cutting so many at one time. My friend is a nurse with three children and she had told me last week because my little niece waas doing the same thing and she is cutting her top teeth. So yes teething could be her problem just be very cautious because RSV is going around right now, I know several babies that have had it. So if you have any doubt take her to children's hospital if you don't feel the peditrician is correct on his diagnoses. Trust me you know your baby better than anyone else, I have found that with past experiences with my children. It could also be allergies, everybody is having problems with them right now, even my little 3 mth. old has had problems with allergies recently. Hope this helps.