I post, and then wonder, should I have said that?

And then I wonder, when I leave - can I leave, will I leave - (I always do) - can I delete absolutely everything about me?

No can do. Words are eternal. But if you can write them down without connecting them to your real self, then maybe they won't do as much damage, or the damage will be stalled long enough, that it will be less damaging, more forgiving, more accepted-as-understandable.