I am glad that you have taken the time to post this sad story. I have been sewing/quilting for years around many generations of dogs & cats (and some parrots). She is very, very lucky to have you. As for thread, if you have small animals or children underfoot (or simply around your sewing/quilting area) please be very careful about not only storing the thread & other supplies, but also counting the pins & needles after use. Prevention is the best way of saving money-and a life.
Please let me know of your kitty's full recovery when that happens.