Do you have fire ants in your yard? My children will swell up like a balloon if they get bitten by fire ants. Not just in the area of the bit all over

Poision Ivey is a devil of a plant. I have heard if you get its oils on you, you can then transfer them to other surfaces, like in the house, where you can keep re-infecting yourself. That would be my first guess from what you have said.

On a towel in the wash room? A table the clothes you were wearing sat on? Door nobs? I'd go on a CSI style crime scene hunt and clean everything that could have possibly touched stuff from the poison ivy incident (or even a new one?)

If you google it i think you will find some good products for cleaning it off (using lots of protective gear while cleaning) and some decent stuff to help cope with the horrible stuff it can do to the skin until you get past it.

Sounds like now might be a good time for you to become quite your own poison ivy expert. I've known two people who have had those kind of on-going nightmares and you can run both around the house with a twig of it.