Walaikumussalam
Smelling something does not invalidate the fast
Fast is valid and in order.
Only smelling of herb are makrooh nor Haram still it will not invalidate the fast just reduce the sawab
While you were sleeping in the day time if in dream something happened and you became najis just you were needed to do the ghusl your roza was correct
Do the qadha of that roza which you have broken just because of the ignorance.
For the future I request try to contact any local alim or refer tauzeehul masayel to avoid such type of the things.
Wassalam
Syed Abul Qasim Rizvi