Oh Marne,
You should at least be able to get hold of out of hours GP if you feel you need to, but I'm not sure what they could or would do.
Ds was like this last weekend after something really upset him at school on the Friday. It took until Sunday afternoon to get him to relax a bit. We took his lead, let him stay in his pjs, watch Pokemon and read. I also instigated a lot of cuddles and let him read on my lap, which although he'd never ask for a hug normally, did seem to help.
For tonight, would it help to wrap her in a duvet, snuggled up to you on the sofa and watch a favourite film. I know its late, but it sounds like her anxiety levels need to come down before she can rest.
Will she drink warm milk? It has substances in that actually help us to relax and fall asleep.
If not, could you ask her to draw what she is feeling?
I did this with ds1 when he was in freefall at the beginning of the juniors but we couldn't get to the root of his axiety. I split a page into sections and got him to do a small/basic drawing in each section:
1 for how he feels at home
1 for how he feels at school in his classroom
1 for how he feels at school in the playground
1 for how he feels with me and dh
1 for how he feels with his brother
1 for how he felt about the 'then' new baby.
He normally hates drawing, but he did a basic pencil picture for each section, then I gave him a pack of felt tips and asked him to add some colour. It was stark, the colours in his pictures at home were all warm and friendly, his school pictures were all dark, he drew sad faces on them and the playground picture was all black with a big sad face in the middle. I nearly pulled him out of school there and then.
I showed it to the Ed Psychs and they said it spoke volumes more than they would expect to get out of him in the few session he was allocated and they used it as a basis for their work with him.
If she doesn't want to draw, maybe try just getting her to come up with a colour for each section instead.