Your doggie looks quite similar to my chihuahua, her name is Coco and she is 14 now. She lets me live here… as long as I admit that she’s in charge and I am just her humble servant.
This is my little devil dog… Harley, he’s a ball of nerves & anxious patrol guard. He’s 12 and doing well except for some personality changes as he is just always on-guard; no matter how much his attention is redirected, plays, etc.
He was raised with another chihuahua that never has anxious moments, she’s rather food obsessed for such a small dog. She receives excellent care, quality food and healthy snacks but never gets enough of course. Her only concern is arthritis really, she gets supplements & anti-inflammatory medications for that but age is catching up as she piles on the years. That why we try our best to keep her lean, doctor’s orders!