Hello! My cat is turning one tomorrow and she seems to be growling a lot more than usual. It started happening after I went to pick her up from my grandparents after a week of vacation. They had a cat of their own, but he's not vocal (they found him abandoned when he was three weeks old -- we think his vocal chords were damaged). Ever since we brought her home, she randomly growls if someone knocks on the door and growls when startled, especially if I accidentally wake her up from a deep sleep. Just wondering what could cause this? Is it from being around strangers and another cat for a week or maybe she is sick?