Hi,
You need to see your doctor. It sounds like your "ailment" is really affecting your over all health and well being, possibly lowering you O2 level which could be the cause of drowziness and lack of concentration.
You may need to use your inhaler 4 - 6 times a day for a few days to get you bakc on the right track.
See your doctor for propper evaluation and treatment.
God bless.
Hello and hope you are doing well.
Steroid inhalers are used regularly for prevention of attacks of asthma. The steroid content is very low in an inhaler and only acts locally. Use will prevent the causative allergens from triggering an attack. It is unlikely to cause any side effects like drowsiness. However, if you are taking anti histamines, to control nasal symptoms they are likely to cause drowsiness.
Hope this helped and do keep us posted.