I only know maybe 3 people that would understand part of what I'm going through.
I try to hide it because I don't want to be a whiner.
Maybe birthday parties are culturally secret "undeath" parties. Part of me wants other people to celebrate that I'm still alive with me. Granted, compared to other people, it's not much of a life, but I want it, it is meaningful to me, and it's mine. These people would feel pretty darn crappy if I died, so you'd think logically that they'd feel happy that I exist. Of course throwing a "hey I didn't die" party would be too weird. But birthdays are sort of the same deal: hey I'm alive, I exist, let's celebrate.