Oh how heartbreaking for you.

I can only offer perspective from when I was a littlie and I was like that - very attached to mum and the safety of mum was far preferable to the unknown of school. I do remember that the longer it dragged out the more upset I would get, and that once mum left I was pretty fine. It was like while she was there I was still in with a chance for her to stay longer or take me home, but once she left I just got on with it and would have fun.

I also remember one day when I was perfectly fine and she came to the school for some reason and as soon as I saw her I started crying and wanted to go home.

I guess what I'm saying is it wasn't anything at school that was causing the problem, it was just that mum being there was making me clingy. So unless she tells you something really obvious that has happened it's probably just separation anxiety.

I hope she settles soon, it must be very hard for you