Whoofah. Whirlwind couple of days. Cleaned the ducts where and how I could (which mainly just meant pulling the registers I could reach and vacuuming out). Scheduling a pro, soon. Cleaned the house as deeply as we reasonably could, then hired a service to do a deep cleaning. Got air filters, ordering more when paydays allow. Replaced the furnace filter again. Wiped down the whole house with citrus-based cleaner, used mold killer and general air freshener where reasonable. Ordered some heavier-duty stuff for future use. Did the same where I could with both cars. They need a good wet washing inside - dog hair and spores. Washed all the laundry. Brushed, clipped, and bathed the dog. Brushed the cats. Got allergy meds updated. I'm deathly allergic to molds and mildews. I'm less-but-still-noticeably allergic to cats and dogs.
The last year I've just been getting sicker and sicker. When it comes to mildew and mold, I get asthmatic after a while. I've been getting to that point. Like, I thought I was having real, honest lung disease issues (I've never been a smoker) and/or circulatory issues. Nope, just allergies. Still generally healthy as the proverbial horse with carrying a few extra pounds and mildly elevated cholesterol.
But holy crap, histamine levels, breathing issues, and air quality around here all had me on the brink of breathing panic pretty much at all times. I'm not sure I can stand living here for the long term; we live right next to wet woods because like most of this general area, it's all clay and flat, and water run off and proper draining back to natural water collection and eco-systems is almost non-existent. So yeah... stuff is always wet and mildewy and moldy. While the house isn't, the woods 20 feet from the back door definitely are.
So it's a mess here.
If you have mold and mildew allergies, you're probably WAY smarter than I am and not living next to the wet woods.
Starting to feel better. Allergy shots (coming up), nasal sprays, pills, and avoiding the wet has me back on my feet and feeling better. Scary how yucky I got to feeling, and how quickly I went from "meh..." to "holy crap, should I got to the hospital before I die?

" in the last couple of weeks. Scary stuff.
Allergies suck. Give them their due attention, and do what you can to mitigate. It all adds up over time.