ploblem

I think you use something and someone more specifically than anything or anybody.
You have bought a lot of things for your family and friends - but nothing for yourself. Then i think something would fit.
Anything means anything junk - not matter what - as a remembrance from a place. Or just to spend money.
Someone would for me be a person a know , anybody is just any person.

These both mean the same (You bought nothing for yourself. Why?):

Why didn't you buy something for yourself?
Why didn't you buy anything for yourself?