I feel your pain. I’ve been there for sure, and I simetimes I get pretty sad/sensitive around my birthday because I’ve had many plans fall through. Reading this thread, I never realized before that this was such a common ADHD experience.

What’s helped me a little bit is to plan smaller, but more frequent, things with just a few friends. It still doesn’t really fill the longing for a great big party for me, but I’ve had better luck with people committing to show up when they know they’ll only be one of 2-5. For example, how would you feel about having a few separate simple dinners with friends in the week of your birthday? As well, I’ve started insisting on potluck style if I ever do plan a larger thing. So much less headache around planning and quantities.

As for what to say to your friends… I get the awkwardness. I’d probably say something like “a bit smaller than expected, sadly”, try to keep the tone neutral and quickly change the subject. I wouldn’t want to lie, but there’s also no use getting into all of it with someone who didn’t show up. That would just bring up a lot of resentment and end up ugly for me.

All the best for your belated birthday, and I hope the next one is better for you.