I don’t know how to express or articulate my thoughts and my vocabulary and grammar gets messed up the more I write so I will just write simply.
What I’m trying to say is that every day or hour or minute or everytime you think, you feels like your original selves is dying. I know that we are constantly growing but i just can’t stop thinking that whenever we grow or learning new things or start to think differently, our past selves is dead. I think back to my past selves in middle school, highschool and from 2022 and think, aren’t they dead? No matter what i do or think or whatever happens to me, i can’t bring back the personalities or "me"s from the past. They remain dead and continue to being dead. Unless they are exist in another timeline or universe.
What exactly is identity, consciousness or the self which is me? I don’t know nor understand but this idea just stuck in my mind and occasionally appears when I’m bored, stressed or relaxed.
I went through a period of this when I was younger. I did not find a satisfactory way of dealing with those thoughts, but they did eventually recede.
There’s quite a bit of philosophy out there abut this. It might help to read about it. Some physics topics are related, like the Planck scale. If you want to read about what others have thought on the topic, here’s a starting point.
So: yes, you’re not alone.