Everybody is different, I suppose. I’ve seen people blossoming post retirement and falling into a hole. The level of enjoyment you felt for the work you did probably is an indicator of which end of the sliding scale you end up on.

What are you, as in you personally, doing about you feel? Learning to live with it, looking for a hobby, volunteer cause, part-time job? It might be presumptuous of me but I’m reading between the lines that you maybe want to continue feeling useful.