Advice greatly appreciated if anyone has the time.

Today is my birthday (go me another year survived)

And two people who were supposed to come and celebrate have called out one is a family member and are feeling unwell so not overly annoyed about that, the other is my supposed closest ‘friend’ like we used to be great friends and then I got in a relationship and the dynamic changed and that causes a bit of strain for a bit, and I’ve always felt I’m the dependable friend that will do stuff when her other friends won’t (they’re the type to meet late and get drunk but won’t be there to help- like she moved and I helped her clean and air the place another friend just came to sit and gossip not helping her move or anything).
But I feel like this is the straw that broke the camel’s back…. I’m having a pj cinema party in my sisters back garden (she’s a godsend I have the best sister in the world) and my friend let’s call her N, understandably her sister is sick and I’m not mad that her sister is ill and I know it’s stressful and she’s been having a stressful time but lately anytime to meet up has been put on hold and post-poned but never actually happens and she often asks me to come to hers except I don’t drive and she does and I don’t live close my nearest station is 40 mins walk away, my cat has had surgery so I’m not able to leave for long periods as it’s early in his recovery. I’ve suggest she come here we can chill in the garden she could even stay I have a spare room, but she doesn’t.
I even gave her an out today and said it’s fine if she doesn’t come her sister being ill and she was saying she was coming but said I can’t be asked with anything anymore and I’m just gonna stay home so didn’t actually say to me she was no longer gonna come, I had to ask. (Her sister is in another country so there is nothing she can do which I guess adds to the stress) again I’m not mad that her sister is sick and she wants to just sit at home alone “stuffing her face like a pig” as she put it. But it just feels like she can’t be bothered and doesn’t care it was my sister and partners birthday a few days ago(friends of hers too) and she just forgot to come because she has a stressful day at work and then fell asleep. I think as well I’m a bit upset is that last night she went out and got drunk with another friend, but won’t come out today. My partner says it’s different cos she’s trying to drown out the pain which I get but it just hurts I guess. Like I don’t ask for much at this point I’m just lucky to be invited I guess, I don’t have many friends so I guess beggars can’t be choosers?
And it makes me feel worse cos my sister is tryna make it all better she made me a Charcuterie board!!! And that makes me feel bad cos I feel I’m gonna be sad and grumpy and she feels sorry for me cos I’m the left behind and tbh throughout my life I’ve always kind of been an afterthought and I guess it hurts more on my birthday? I don’t know I just have a lot of feelings rn and I don’t even know if this makes sense! Like I’m genuinely sorry her sister is not well, she’s a lovely person and I feel bad for being grumpy when she’s not well and it’s just my birthday… I dunno by the end of writing this I do feel a bit better and maybe I just needed to vent.

If anyone makes it this far in my rant, I wish you all the abundance life has to offer and to have a great life!