31/2 year old severe cough spasms Day and night

[parvie]

My son has been diagnosed with Asthma @ 2 1/2. He's on Flovent 2 puffs twice per day. When He's sik from Cold I put him on Albuteral and Pulmicort twice a day with Nebulizer. It works well. Beside twice when may be I wasn't able to start nebulizer soon enough and albuterol just didn't work anymore and he had to take orapred for 5 days(total10 days). He also got Croup a year ago. So bad that he was hospitalized and was given steroid shot. Since then his croup came back twice but each time I was able to manage it at home with shower steam, humidifier,albuterol and pulmicort. This time on Jan 28th he woke up in th emiddle of thenight with Croup sounding cough so bad that I had to give him Albuterol right away. Croup sound was gone in 2-3 days but the regular sounding cough with lot of mucus is going on for more than 3 weeks now. I have taken him to doctor twice. First time to pulmonolist who said his lungs sound fine may be he has sinus infection so prescibed Amoxicillin. After 5 days on antibiotic I see no difference in cough. Now agian I took him to physician( not specialist becuase they're closed on Presidents day). She said his lungs sound fine. Just don't give him anyhting other than lot of fluids and suppreesent at night so he can sleep. But even suppresant doesn't help he wakes up every 1-2 hours with cough so bad he's been vomiting lot of mucus for last two days. Last night i even felt as if he was turning bluish and not responding to me for good 10-15 seconds.Please advice what else can I do to make my baby's days/nights easy..Thank you so much (I apologize for all the spelling mistakes)