Send to school or not?

[1potato2po]

Name changed for this

DD woke up last night around 3am complaining of a headache and tummy ache.
Vomited once (just water) around 5am and went back to bed fine. Left her to sleep and she woke up about 9am and stayed off school.
She's eaten breakfast, lunch and dinner, played with toys, watched a film and generally kept herself amused today. You'd never know anything had happened. No temperature or anything like that, feels normal and fine.

Would you send to school tomorrow? Would be about 16 hours roughly since she was sick.

I don't think it's any kind of bug, as I assume she would have been sick more than once?
DD is 11, in year 6

Don’t schools have rules about this? Eg 48 hours after being sick before they can go back? Otherwise, I would send her.

I'd send her. Sounds far more likely she ate something that didn't agree with her.

I don't think it's any kind of bug, as I assume she would have been sick more than once?

I wouldn't assume that. We've had a bug that made both my DDs and DH all vomit just once. It wasn't something they ate, they all had it a couple of days apart.

She's been sick so no you don't send her in for 48 hours. You can't possibly know it's not a bug just because she's only thrown up once.