The short answer
Your confidence did not disappear — it went quiet because the job was the thing that kept confirming it. Coming back feels like starting over, but you are not the same person who left. You carry everything you learned. The work now is finding that proof again, one small win at a time.
I keep coming back and feeling like a stranger in my own career. That feeling is real, and it makes sense. Research on work and identity shows that a lot of who we feel we are professionally gets built and rebuilt through daily work — the tasks, the feedback, the title, the rhythm. When that stops, even for a good reason like raising kids or getting well, the identity starts to fade at the edges. You did not lose your ability. You lost the daily confirmation of it. That is a very different problem.
Marcus Aurelius once asked himself how many people who were alive when he was young had already gone. He was not being grim. He was reminding himself that time moves whether we watch it or not — and that surviving the move is itself something. You came back. Many do not get that chance. Research on returning after a break shows that people who rebuild a work identity tend to do it not by reclaiming the old one, but by building a new one on the same foundation. The old you is not gone. It is the ground you are standing on, not the ceiling you have to reach.
This week, pick one thing you used to do well at work — one specific skill, not a title or a role. Do a small version of it. Write something, solve something, help one person with one real problem. Do not aim for proof that you are back. Aim for one honest moment where you felt useful. That is where the new identity starts — not in a title, but in a single act that reminds you what you actually know how to do.