I'm autistic, diagnosed as an adult and now in my mid 40s. I've always felt really sad on my birthday and feel under pressure to be happy and do fun things.
I can never think of what I want to do and I just spend the whole day with a fake smile pretending I'm okay with the day but no matter what I choose to do I hate it. I'm so relieved when it turns midnight again and the pressure is off.
I love family member's birthdays though and know exactly what to do then, I really enjoy making them happy.
Wish I could just stop being a misery on my own day though!