No one did anything for me on my birthday.
No, I figured that the important people would just remember that it is my birthday.
I just don't know how they could be so ungrateful to me late in my life
It's frustrating to be alone on a special day, and it's fine to want other people's attention at those times.  However, many people simply get distracted by day to day events and don't remember others' birthdays.  It's not that they don't care about you, it's just that they simply didn't realize that you were expecting to hear from them.
I wished everyone a happy birthday on facebook.
I get that it is frustrating when you remember everyone else's birthday. I think that it is understandable that you are upset, but you should try to just spend the day doing something that makes you happy.