To not show up

[Shiny88]

My LG aged 3 had her first gymnastics competition today, my mum (her nanny) said she would come.
She didn't turn up and I couldn't get hold of her.
(I know for a fact without even asking her it's because she got drunk last night and is nursing a hangover).

I'm livid and so cross that she didn't turn up.
AIBU? Or this this just coming from a place of hurt from my childhood?

What's the question exactly?

Very rude of her not to let you know, but I think you are right is feeling your reaction may be from that hurt childhood.
Is she a good nanny otherwise?

Is she an alcoholic OP? Or just unreliable? Either it seems like this is a pattern you've had to put up with your entire life and it's absolutely understandable that you're hurt and resentful. Might it be easier to save yourself future disapointment to not invite her to events like this?

I hope your DD enjoyed her competition and the day wasn't totally ruined for you.