I think that Annie knows that Bella is gone now.
This morning, as I rose from bed, I heard Annie whining. She was walking around the bed in the Blue Room, moving from one side of the bed (her side) to the other side of the bed (Bella's side) and back, whining loudly. She paced a couple times as I watched, then settled down in front of the space on Bella's side of the bed. She does that when she wants to block Bella from going some place; I interpreted her behaviour as Annie positioning herself where she knew Bella would pass.
Kris was worried Annie would pull a Red Fern (in reference to Where the Red Fern Grows, which is one of my favorite books, but has a very sad ending, where **SPOILER** one dog dies immediately after the other dog. I didn't think she would, given how much she was acting out last week, completely regressing in her discipline. She had been running around the house, being a crazy dog, digging through bags, stealing anything that was plastic and chewing on it, checking out items on the counters.
Today seemed different.
She's moping now. I think she knows that Bella is gone.