[mscat]

If i were you I would take Bella with you. I would not apreciate my mother doing that to my dog/baby.
Your an adult and i believe she has disrespected you and your wishes . I'd also do whatever you can to get out on your own . Maybe even lieving with roomates for a while or shared rentals could be an option.
i know you probably do not always want to be in conflict with your mother either, and I do feel that in this case she has totally step over her boundaries.
Your mother has already made it clear of what she is going to do when you leave. I would not leave your baby with her. Start making alternative plans for Bella , more so for her saftey, and your peace of mind.
I am sorry your mother is not supportive and making things stressful on you. This is your baby though and your respnosibilty. So do what is in the best interest of your Yorkie, and what works best for you.
Animals can't speak for themselves, and I personally would never leave anybody in charge of my Suzi if could not trust them. Regardless, who it may be.