The depersonalization you describe is natural, a defensive reaction to severe psychological trauma. You can call is unresolved grief. It takes a while to fade, and I would be surprised if it ever went away completely.

You are looking at the contrast between who you were and who you are. It may help to remember that those two are never the same, for anybody. Events always change us. Heraclitus said no one can step into the same river twice, because the river is never the same river, and the person is never the same person.

What is different for you is the cataclysmic impact of that one event. Most of us feel a continuity with our past selves, because the daily changes accrue gradually and are automatically incorporated into our ever-evolving sense of who we are. You can see how you have changed in the past 2 years and see yourself in all of it, but the change of that phone call was too much a break to weave into the tapestry. Too many threads were torn.

The important thing to keep in mind is that your current self is the real one. Hold onto that, and live the life you have today.