@aimsez86 First, I would look around for other culprits before I would jump to mold testing. The symptoms suggest it could be allergies (not all allergic reactions include runny nose and itchy eyes.)
There are many things in the home that can be irritants, and when you stop mixing fresh air with household air, these increase in concentration very quickly. Here are some obvious culprits - scented ANYTHING - detergents, household cleaners, personal care products, air fresheners, odors emanating from clothing after work, outdoor air pollution/smoke/pollen sneaking in, dust, emissions from an unvented dryer, bathroom or range hood (all should be vented out of the house), or ...

Try switching to unscented products, using a damp mop and cloth to dust frequently, using a vacuum cleaner with a (frequently changed or washed) HEPA filter to clean carpets, upholstered furniture, radiators and heat or cooling vents. Here are more suggestions from an allergist years ago - wash bedding and towels frequently in hot water and dry in a machine, remove as many "dust catchers" as possible - curtains, blinds, stuffed animals, decorative pillows. Wash or vacuum the remaining ones often.

Have you tried running a HEPA air purifier? We find it helps a great deal.