totaly know what this is like, my dd5 has had probs with airways, asthma, coughs, and then croup. Most the time i have no idea which is which, and the poor mite ends up taking meds, and inhalers and gets covered in vocks. All seem to be to no effect.
Gp once gave us a steroid tab to dissolve in water, and spoon feed her, this worked.
Next time she got it, about 3 months later, i asked for this tab and the gp didnt really want to give it. I gave it to dd and it didnt work.
Yet the next night she was much better, so it may be the 3 day/night thing.
You poor thing, i am on my own with dd, and I know its totally diheartening to hear, and to know you cant help much.
I know that when they go off too sleep and they stop, it only takes a shift in bed, or me to walk past the door and disturb her and she can start a coughing fit.
I hope that tonight really ens up being the last night for you. take care.