I've started limiting sleepovers for DD (soon to be 11) to no more than 2 other girls at a time.
Last year for her birthday party, we had 10 (most from her newly-formed softball team), and the DRAMA!!! The problem was really that the girls didn't know each other particularly well.
All night long it was she likes her, but is bugging them. Three groups of 3-4, and then they'd blow up and switch groups. Never, never again. DH was out of town and I truly thought I wouldn't make it.
Yes. I hid. With a glass of wine. And I'm proud to say I'd do it again in a heartbeat. When I got up in morning, 2 were in her room, 5 were upstairs in the living room, 4 were in the basement. Apparently there was a division of those who wanted to sleep and those who wanted to stay awake all night.
They say time heals all wounds. Not this one. Never, never again. And I'm the "fun" mom.
Hope you survived!