Croup in baby

I'm a first time mummy and I have lots to worried. My 2mths old little one had this weird noise as if hard to breathe noise once awhile everyday and so I brought him to kkh. Doc said it's croup and he was given steroid. After 2hrs of observation, doc released us to go back home. My concern : during consultation doc mentioned that if child below 3 yrs old will need to be warded but he said my lil one is okay. But asked me if I'm confident to go home ? How am I supposed to be confident now when he said so? But still I brought him home and monitor him closely. How long will croup last after steroid? Will it get worsen? On and off he still have the weird inhaling noise. #firsttimemom #firstbaby #advicepls #anxiety