FLovent inhaler in 6 year old?

My son just started using FLovent inhaler for his asthma. I'm concerned about side effects-most notably, he's now afraid of any noises during the night, extreemly anxious about them. Now he started this medication at the same time that our state experienced some out of the ordinary strong thunderstorms/tornado's, so i'm unsure if this anxiety is a result of that...or the anxiety is increased due to medication? i'm looking for good/bad with the flovent? advice? we're just learning to navigate the asthma world, as the diagnosis is relatively new.