So hurt and upset by my step mum!

[Mytype]

So longggg story short it’s my dads 50th this month and I asked him in dec what he had planned and he smiled and said it’s not for him to organise. So I’m thinking right il message his wife and get things organised as we live 5 hours away etc. She messaged saying she is taking him away for the evening and then her daughter to doing a surprise tea nothing major. But no invite so I continue to tell her what my dad said and she just kept repeating herself that her daughter was doing something for him so okay.
A week before his birthday her daughter messaged asking if we would like to come, but now I have a week to try and get some extra cash for petrol, try and get time off work etc!
I spoke to my Nan the other day who mentioned she got invited weeks ago! The same day I asked my step mum what the plans for. I’m hurt and upset I don’t understand why they have left it this long to invite me when they know I have a son and Xmas etc and they tell me I’m going to have to get a hotel if I come down? Am I right to be upset I kinda feel like it was deliberate. My step mum made it clear that nothing was being planned for his birthday however she invited my Nan for a surprise tea but didn’t think to invite his daughter. I have raised my opinion and I’m just being blamed and kinda oh well attitude

There are enough people involved in this that I would give them the benefit of the doubt unless you have a history of issues with them.

Step mother told you about the tea, she didn’t keep it secret. She may have thought that her daughter should invite you since it sounds like daughter is hosting. Daughter may have assumed step mother invited you when she told you about it.

Benefit of doubt unless there is a backstory.

We have had plenty of issue in the past and my brother hasn’t spoken to my dad for 3 years because of these issue involving step mum

You are five hours away, work, have a dc, and Xmas and all associated expenses are just past. I wouldn't expect you to attend a small afternoon tea thing requiring an overnight stay in a hotel, and probably wouldn't think to invite you, tbh. Sorry.

I think step sister probably assumed you wouldn't be able to make it just for a birthday tea as you're 5 hours away and has probably been prompted by your step mum to ask you at the last minute.
Of course we don't know back story but on the Face of it going by what you've posted so far I wouldn't be taking it too personally.

I think you should've thought about organising time off/transport etc beforehand as she mentioned something was happening and I assume you'd have visited your dad on a big birthday regardless BUT I think you've every right to be upset. You've clearly been told last out of everyone when you're the person who probably needs the most notice! If they were nice people I'd just brush it off, but if you've had previous issues I'd say they probably didn't tell you until it was too late for you to organise so you couldn't come