Allergic to my house

So I'm allergic to my house. I've never had any allergies in my life until a few days ago. I'm racking my brain trying to figure out what it is from. I keep breaking out in very itchy hives and they keep spreading. I had to go to Urgent care to get a shot, didn't help. then to the Doctor's and they put me on steroids, not helping! This sucks! If I leave for a few hours they seem to clear up a little so I think it has to be my house. Jeff offered for me to go stay in a hotel - with all 3 kids! Yeah right, he's dreaming :P