Thank you all for your responses, it's so kind of you all. I know you're right - these ops are done every day and her surgeon is, according to Mr Google, amazing. My head is telling me that she'll be fine but, oh, I'm in bits today. I've taught four lessons this morning and have no idea who was there or how any of the classes (online) went (apart from one which was terrible)! In hindsight, I should probably have taken the entire day off but thought it better to be busy for at least part of it.
I have put the flowers in water, thank you...