Freaking out!

I just got the mail and I had a packet fromt he SB County Health Dept. We had my 15 month old, Daniel tested for lead levels 2 weeks ago at his well baby check-up with his regular doctor at Beaver. We did it becuase we have an old house which was built in 1918. He has lead posioning!! The letter from the health dept said he has a lead level of 13 micrograms per deciliter. Normal is less than 10 and most people have between 2 and 3. I called my doctor and they didn't even have the results yet. I just faxed over the document I received. I am going to need to have my 5 year old tested as well. I am really needing prayer that we figure out what is causing this, and are able to make improvements.
I am feeling like a really crappy mom right now because in the information we were sent it says stuff like a dusty house and using a belt sander and keys are a big source of lead poisoning and that kids need to eat healthy diets to help keep lead levels down. I never knew keys were a source of lead and both my kids would play, and suck on keys as babies. We have painted our house, and sanded the floors in the last year so now I thinking of all the things I have exposed my kids to by doing that and by not keeping the house spic and span. I am doubting their nutrition, and their home environment, and all their toys. My stomach is in knots thinking that this could have been avoided. Please pray for me.