There doesn't have to be a lack of structure; I’d strongly advise you to start planning now.
Not having a regular regime is what defeats and depresses a lot of retirees.
When we are working, we’re useful; contributing to our community, society and family.
Once our job goes, if we have not considered the whole person we are, self-esteem might too. So it’s vital to find a way of still contributing.
And only you can work how that’ll be accomplished.
You are harry1960 with all the multi-facets which make the whole person - being a worker is only one small part of who you are.
Now it’s time to identify, value and use all the other things you can be.
I had a friend who was a keen golfer and talked for months about how he'd spend all his days on the golf course once he retired. And he did…for about 6 months then much as he still loved the game, began to feel self-indulgent and, even worse, useless.
He’d been a senior lecturer but now felt he had no real/important role in life. But he began to acknowledge all the other facets of his character and personality, looked at things he was and could do and reinvented himself – and his self-worth.
You need to do the same – but don’t wait until you feel you are useless and have no purpose, you are neither - so plan now