it could be dust mites or dust or dander or spores or even the kind of detergent or fabric softener you used to wash your sheets from your bedding or your bedroom, It may be causing similar symptoms like some allergy symptoms.. . maybe wash all your sheets and blankets, vaccuum the mattress (make sure you wash the vaccuum attatchment/brush in something antibacterial or at least regular soap water before you rub it all over your mattress), get a new pillow, wash away the dust-bunnies under your bed ! wash your windows (there might be mildew that you may or may not see), open the windows to air out the room occasionally, just after you get up or just before you go to bed, get fresh air for several minutes or 1/2 hour. Any or all of this might be a big help.