OO ds has been like this to some extent.
He started off crying on the way to school, and lots of crying when I left and also cried throughout the whole day.
Then after a week or so he stopped crying throughout the day and then on the journey.
Now he is sad when I leave but doesn't cry. And he is happy in lesson time but cries at lunchtime.
When my friend took her ds to pm nursery last week, she saw him in the playground sobbing and clutching his cuddly dog . I booked a meeting with the head after that. She said I could take him home for lunch and either keep him home or bring him back for the pm session. I didn't do either of those though as he has been making progress and he is now happy in class time.
But the teacher has been great. She's giving him stickers when he comes in happy after each part of the day ( i.e after break , lunch etc) and has given him cerificates when he's been happy most of the day.
He takes his fave dog with him and is allowed it whenever he likes. It was in the going home box when I collected him today. Thats a good sign as he wasn't clutching it. For the first few days it was stuffed down the waistband of his trousers. Is your dd allowed to take in a comfort toy?
He does have friends though. Just says the day is too long and he misses me.
I have got a few good books. One from Red House books called starting pre school I think. And one from matalan actually.
And finally, sorry I've rambled, I've been bringing him lots of treats when I collect him. They were from the 'staying at school all day pixie'. I know!
First when he was very upset it was a mini transformer or a 'cars the movie' car. Then they spaced out to every few days then now its the odd sweet etc.
HTH