Okay, my cat is 13 years old and will be 14 this september. Lately, all the hair on her belly and under her armpits it is just falling off. I mean, I can lightly tug on her hair an a humoungus clump will come off with absolutely no problem. Is this due from a lot of stress? Or old age? We have a dog as well that likes to try and tease her all the time. I know it isn't fleas or allergies because we never changed her food, water, or litter. Please! I need an answer!!!!