How can I help my daughter through this?

[AintNobodyHereButUsChickens]

She's just started Yr3 so she is 7, she's been back at school since last Wednesday, and yesterday, her best friend left to go to a new school nearer to her house. My daughter is absolutely devastated and spent most of yesterday evening and this morning crying :( They've been friends since they met at nursery aged 3. Me and the friends mum have said we will arrange for them to play at weekends and holidays but DD is just so sad. Her BF sat next to her in class and was also her lunch partner so now she has no-one to sit next to in class or at lunch. I just feel so sad for her, she's recently had a huge upheaval when she became a big sister and she's struggling with that and now she has this to deal with this.

How can I help her?

Speak to the school. They should not leave the void that has now been created, and not allow your dd to be alone in class or lunch- that is just wrong. Call the school NOW.
My dd's bf moved away when they were 8. They had been extremely close (as are me and her mum) since babies. Dd is a resilient child and this has helped her, but she wasn't devastated. We see each other each school holidays, they facetime etc. I'd therefore question is perhaps the shift in family situation more of an issue than you realised? Have you discussed this with her?

My daughter would be devastated if it was her best friend as well. It’s very hard for them because at that stage, friendship groups are very well established (though we found that things jiggled about a bit when she was in year 3 last year). Perhaps have a word with the teacher & see if your daughter can be buddied up with someone else?

try & see t is a good thing - she’ll have a chance to make other friends & she still has her bestie as well xx