Sympathy and understanding does WONDERS for parents like this. We tend to think that the child is doing all of the adjusting but the separation thing can be harder on the parents sometimes. Many parents feel like no one can take care of their child like they do. but you know what? they are right. you don't take care of them like they would, as you are NOT THEM. But, that doesn't mean you don't do a bang up job. Telling her that you are sensing that she's having a hard time with this separation, having a dialogue about it, then moving on to the feeling that this is causing a trust issue between the two of you might very well calm her. Once she is calm you'll probably see a whole different side to mom.
Been through this before a few times. I know that its super irritating but smiling through it and empathizing has NEVER done anything but good.