My poor LO has had cold symptoms for just over 4 weeks now

We took him to the pediatrician at the beginning of the cold, about a week into it, and have called them since to keep them updated and see if we should do anything more. I'm starting to think he may now have croup, his cough sounds so sad! He has his 4 month checkup on Thursday so we'll see what our doctor says then. He hasn't gotten a fever at all though and really hasn't been all that fussy. Just congested (not affecting his nursing though) and coughing (which is waking him up at night). Does anyone else have experience with a cold/cough in your LO that just won't go away?
Re: Baby's cold is NOT going away!
Bracing myself.
I keep wondering if a dose of antibiotics would just knock her stuff out as well....
I also wonder if it is croup.
Or an ear infection.
Or teething.
Ugh. Wish I was a pediatrician right about now.