My allergies to house dust are worse at night to the point were i can't breath. i've already taken a 24hr allergy pill. how do i get rid allergy?

Get a new pillow: You current pillow is likely covered with mites. Throw it out and get a new pillow. Put newly washed sheets on at the same time.

Environmental change: I would suggest changing your pillow/sheets and using mattress covers to avoid dust exposure during the night. It is also helpful to remove carpets/stuffed animals from the bedroom. Hardwood or other non carpeted surfaces are much easier to clean. In addition, I would suggest that you speak to your physician about pulmonary function testing.