In your home, which may be well sealed against the winter chill, mold often grows in damp basements, closets, window sills, bathrooms, garbage pails, refrigerators, mattresses, house plants and anywhere else that conditions are right. At your place of work, they'll grow in the same types of places. Office buildings may have ventilation or climate control systems that can be ripe for mold occupancy if the vents are not properly maintained. The story gets a little more complicated. Your allergy symptoms don't correlate to the mold itself, but to the release of spores into the air.
Different molds send their spores airborne under different conditions.
For example, some release spores only in dry, windy conditions. The upshot is that your allergy might kick in when you least expect it. Use exhaust fans in bathrooms and wipe down the shower after use. Periodically clean the bathroom and other moldy places with a product that kills mold and mildew. Empty your kitchen garbage can every day and keep it clean and dry.