itchy skin rash question?

So we recently began remodeling our house, and tearing down all the old sheetrock, the house is around 40 years old, so the sheetrock was pretty gross, plus there was old paneling on top of it. That is when it began I can go back in that part of the house or i get a rash everywhere. I have never had a rash before this and it is so unbearably itchy. I thought maybe my skin was dry so i tried lotion, and it helped a little but now it seems to strike at any moment of the day, when i am at owrk, or out of a restraunt, i can just looked down at my arm and the rsah is back. We also recently started using a different laundry soap and I dont know if thats it either. So my question is, if it's the sheetrock, I mean is there something in any of this that would cause this horrible rash. No one else in the house is bothered just me. Any help or advice would be great!