to be upset with my dm?

[Back2Basics]

So I went to a really nice resturant about 6 week ago, while there my dm rand me and I said how nice it was and that I wanted to take her there for mothers day. She said oh that would be lovely.

A couple days later it was mentioned again and again she said it would be lovely.

then she said she wants to see her mum really as she's probably not going to have lots of mothers days left, which is understandable and then we made firm arrangements for the Saturday before.

Now she's just rang me to say my sisters taking into town for lunch. I'm actually really upset that she's going out doing what I wanted to do with her.

background info my sister was always the golden child and firmly my mum's favourite growing up, I left home early and it's only since I had dc myself that me and my mum built back a relationship 6/7 years ago.

am I overeacting to be upset?

Why didn't you invite your sister and your grandmother to lunch? You could have all spent lunch together.

She does bother with me but it's when she's realised we haven't seen each other in a while.
It's like a tick on the jobs to do list more then genuinely wanting to see us I feel.

I do think she's sorry but I know I'll be made to feel awful for upsetting her now. My dm is the queen of emotional blackmail.

I'm not going to run screamimg for the hills I just won't be inviting her to do anything again in a hurry and never on mothers day.