Primary school unauthorised absence?

[wombleflump]

AIBU my DC started school during the pandemic and now in year one. Due to the chaos of school closing and rules I have been relaxed about things. Unfortunately my DC has a vomiting bug the week before Christmas and had to miss her last week including the play etc. She was upset about this but she was literally throwing up everywhere! So anyway the school announces after the new year that I need to produce a doctors note, appointment letter or prescription medicine otherwise the absence is unauthorised as was five days before the end of term. This is the first I heard of it.
Should I have know about it?
Obviously she doesn’t and didn’t need any of this evidence for DV.
They told me not to bring her in when I called in entered it on the app!
Am I being AIBU?
Now I feel a bit rubbish about it.

Yes I didn’t know they would record late as
Absence. Wish they had said. As I said I have already admitted I’m in the wrong about getting in on time .

Op you can’t beat yourself up over something you didn’t know. I know I found it hard when mine moved from nursery to school . You know now moving forward.

Op don't beat yourself up. You're clearly dealing with a lot at the moment, and you've made a clear plan to get better at timings going into the new term.
Try to make sure you're getting a break for yourself too