Aibu or have i got a right to be upset/annoyed

[Donut22]

So broke up with my childrens dad 2yrs ago, he's what I call a fb dad now,
He is spose to have our children every Sunday he picks them up at 1 till whenever could be 3 or 8 there's no routine with him.
Anyway I say he picks up every Sunday, 1st my youngest (who's 6) 99%of the time won't go with him, it has been 3weeks since we have seen or heard from him expect on the Sundays 2 say he can't make it.
Well of course he has them today 4 Xmas posts all on fb how lucky he is,makes himself look like a fab dad 🙄comes to dropping them off and oldest decides to stay with him the night tells me 2mins before they arrive so I can pack her bag.
This is the 2nd time this has happened it was 6weeks last time then he saw them again n eldest stayed telling me 2mins before hand
Aibu that I feel hurt/annoyed by this.
My eldest dotes on her dad. Sad to say it breaks my heart this will be the 2nd time she's ever stayed away from home I look after my kids 99% by myself he just swoops in when he likes n goes again. He doesn't do anything with them just goes to his mums or his flat, has never took them anywhere not even a park, yet my youngest isn't bothered my eldest pretty sure she would live with him if she had the choice.
Breaks my heart

Any1 😔

You're not unreasonable to feel it's unfair. She's just a little girl trying to get her Daddy to love her though, and it's sad he isn't more interested. Maybe best to try to make things a bit more formal with your ex, so that you know when to expect she's staying away, that would sting less.

Ahhh thats true bless her, There no talking to him, I said a lil warning would've been nice to I don't need to ask to have my child, child he's let down 3weeks on the run.... its funny he has a total of 6kids and just sees our eldest sometimes the youngest very rare tho. Doesn't bother with any of them. Think I must have separation anxiety I just hate it she's not here with us I no its only 1 nite but I can't stand it 😔

Enjoy your time with your youngest. Your DD is with her dad and having fun. You're the default parent who is always there! She will understand that - right now she misses her dad. I did too at that age and I'm sure my mum would have written a similar post to you. I know my dad for what he was - my mum put in the real work...