Cat suddenly in recession against humans

We found our beloved cat, Katie, as a stray. ( There's some pictures of her here: http://www.flickr.com/search/?q=katie&w=75208813@N00 ) She's a beautiful Bluepoint Siamese in her genes somewhere, we're sure, but she loves people.

Well, normally.

Yesterday I was petting her. The usual... stroking her head to tail, over and over, she was purring, loving it as normal. However, during one stroke she just up and hissed and threw herself back and now she hates people!

We spend our time on the second floor of our house, and while normally she's in every room you're in, she's spending all her time in the unused bedrooms or downstairs basement, just away from people.

When approached, she gets suspicious and runs away and hides.

What have I done??

-Matt

PS. If it means anything, she did give birth to some kittens about 4 months ago... they all found homes ... http://www.flickr.com/photos/matthol...7594364203791/

Could you possibly have either 'sparked' her by having rubbed your feet on the carpet, or by touching a sensitive place (even a new abscess) under her fur, or was there an unexpected noise, or smell, etc. at the time? You have to do the hunting here. But have you very quietly gone to where she's hiding out, sat down, talked to her a while, wiggled her favorite toy, brought her a treat, etc.? All of these things will help to lure her back, and don't wait (though once you start it could take a day or two) because she's forgotten by now what happened, only remembers the feeling, and won't come back til her concentration's broken.

Hey, those are some great ideas ^_^

I might try that... spark/static shock is a possibility since it's winter and the air is dry, and sparks are somewhat "in" these days.

I guess I'll have to try some of those things. Thank you!

-Matt