Cough and congestion for a over a month!

Has anyone experienced this, especially in the Winter months. 

My LO is 7months and has a mucasy cough n blocked nose for over a month now. i keep going doctors and they say its fine, they say he has broncholitis and it will clear on its own. No meds as its viral.

he has on off fever and it gets better then gets worse. Hes now lost his apetite so ive reverted back to milk (hes on solids) to keep his fluids up.

but its just my gut, surely coughin and wheezing for over a month is not normal? Regardless of the time of season!