Ok, so birthday weekend for me this weekend 
But.
No plans due to lack of money/babysitter etc.
My mum asked me what I was upto. I said nothing for the above reasons, but might it be nice to pop in to hers on the day after my birthday. She was all for it.
Today she asked me again what I was doing. 
Then she told me that her bloke's mum is having a birthday do at her house on Sunday (her birthday is about 3/4 days after mine) and that she 'has' to go to it, which means that not only do I get to spend my actual birthday without seeing anyone and celebrating it, the one time I could have 'my' day has gone
AIBU to have a slight strop about this?
And before we all flame me 
I am aware I am an adult and this shouldn#t bother me
Just felt like having a moan