In what place within me did I live?

Drop by drop, grain by grain
I return to being the old one, the new one, the one I have always been, the one I will be
And I lost myself
Because children are so sure of themselves
Teenagers don’t know where to go
And I, well, I lost myself
A hole I dug until I lost my strength
And when I reached the bottom, I just cried...
For I had lost myself
And if I wore a mask to try to be pleasant
I did not know how to be pleasant to myself
For I was no longer me
And if I numbed myself to forget about me
Well, I succeeded because I lost myself
Others possessed me more than I possessed myself, and I allowed it
I was just lost...
Who was I?
In what place within me did I live?