Trekjeni,
I am sorry you lost both of your kitties so quickly. I have to say that is the strangest cat death story I have ever read.
Once upon a time, I had a cat get very very sick. She hid, and she was not a shy cat normally. it took us hours to find her too; we had a partially finished basement and she crawled into the dirt part to the farthest possible corner. We took her to the vet where she had a fever of 106 and he wasn't sure he could save her (he did) she had a septic pregnancy so he removed the offending organs and she lived another 12 years.