My kitten was playing with a bug a little while ago, stalking it and pouncing on it without killing it, when all of a sudden she started going crazy. She was shaking her head violently, and opening and closing her mouth as if she had peanutbutter on her tongue. A few seconds later, she started foaming at the mouth, long strings of it falling onto the floor. This went on for over a minute. I'm a little panicked even though she seems to be doing all right now-- I've never seen or heard of that happening to a cat before. How worried should I be??