Maybe this will sound childish, but I am really about to throw my toys out of a pram. Please bear with me...
I am in this friendship group over a year, we celebrate each other's birthdays and other occasions with nice meals out. About once a month. So far I haven't let anyone down. But now my birthday is coming up. One by one, friends decline invitation as they have something else on. Yesterday, i get a call from a friend A (who i thought kinda close and also she takes charge of organizing things), she said not to take it personally, but this is just inconvenient, and she and others have other plans. How about we postpone it for a month or two when everybody feels up to it? In her words... "better things to do in September". So I called her a cow and told her not to bother to invite me when its her day. I will also have better things to do.
Later, I get a call from friend B (obviously contacted by the friend A), she apologises, and suggests we should meet up in a middle of a week in a pub instead. I said i will think about it. But i really don't feel like going anywhere now.
So...
IABU - i need to suck it up, nobody owes me a night out at this specific time, and just go to the pub with them when its more convenient.
IANBU - they really don't like me and i shouldn't bother with them either.
Side note: friend A asked me to help her with a little community project. I would have loved to, but now I don't think i want to devote any time or effort, if a night out is such a mission impossible.