We got a new kitten a week ago...it was about 3 months old...it was very friendly and fit in with our family right away...she was litter trained and everything (someone had "dropped her off" at a friends house)..she seemed healthy, she at good and drank good...so then about 2 days ago she started staying upstairs away from all of us...she had also pooped on the floor upstairs, once was like diarrhea, then I brought her downstairs yesterday, she was very weak and wouldn't eat or drink but she moved herself around a bit but seemed fairly listless...last night I gave about 2 1/2 teaspoons of water through a medicine dropper to try and keep her from dehydrating...she was dead when we got up this morning...what could have made her so sick and killed her?