I was wondering if it was not the dog, but whatever was on its fur. Maybe that got in your house? I would wait and see a few days, vaccuum a lot, dust, etc. I know you're suffering with the breathing thing, but it might be worth a try.

If what was on him was bad enough to cause that much of a reaction, it may be there's enough in the house that came off him, that once you get rid of it, you two can get along okay.