We had this a few years back. Wife got bit but I did not. We shampooed carpets and furniture, washed linens, etc. After a few weeks it went away.

I'm a bit worried about all that RAID. You might consider a Bug Bomb. Set it off and go on vacation for a day or two. Then wipe down surfaces. I personally would do the above cleaning first though.

The gnats you saw are likely fungus gnats as you suspect but they aren't your problem, they don't bite. The adults are completely harmless to anything at all, its their larvae in the potting medium that can present damage, by feeding on plants fine roots.

Tricks for ridding your kitchen of fruit flies like the vinegar don't work for fungus gnats as you've seen. The adults have very brief little lives, its the breeding cycle you need to stop. Get some form of one of the BTi products (Bacillus thuringiensis subspecies israelenis). The subspecies is important, its specific to mosquito and gnat larvae. Gnatrol, Knock out Gnats, others, or in a pinch buy a package of mosquito dunks, drop a dunk in a container of water, let it sit overnight and use that water on your normal watering schedule for container plants, each time you water, for at least three weeks. It takes a while to break the breeding cycle but be patient, it will eliminate the gnats so be consistent. And the BTi is non toxic to you, your home, pets, birds, harmful only to mosquito and gnat larvae.

I don't know what's biting you, it's not fungus gnats. Their larvae stay in the potting medium, either in the bag or your pots, and they aren't causing your itching either. Whether there was something else in that bag, or if the timing was completely coincidental, I couldn't say....

We had fungus gnats bad one year, they came in with a new potted plant, by the time we figured out what they were they had infested every plant in the house. They were so bad the only option was to get rid of all the plants. I also set out cups of vinegar covered with Saran Wrap with small holes. I always caught a ton, but it made no difference at all until I got rid of the plants.

But, they never bit. Not me or my highly sensitive hubby or kids. I hate to even utter the word, but you might look for bed bugs in the absence of any other obvious bugs. My SIL battled bed bugs after her son brought them home from his Disney trip with the grandparents. Ewww for sure, but they are out there.

What else have you brought into the house? New bedding (discount 'new' mattresses are sometimes recovered old ones), used furniture, thrift store items? I'm thinking perhaps you're dealing with bedbugs? You can bring them home in your suitcase from a trip, even.

As to you getting bitten, and your husband not--I saw an article just recently that some bugs prefer certain blood types. Also, people who take vitamins are less 'delicious' to bugs. If you don't, you might want to start taking vitamins until you get a handle on what's going on.

What about fleas? You can bring them into the house on your shoes/clothes, and sometimes, if an area is bad with them, even if you don't have animals.

If you're being bitten during the day, it's not bedbugs. They come out at night and bite while you're sleeping, which is why they call them bedbugs.

I think you have no-see-ums, fleas or some other very small biting insect.