As a piece of advice to the OP, I'd guess this is probably true. He/she seems like a very driven person, who derives a great deal of personal identity from work. As a piece of general advice, it's probably true for most people, but it certainly didn't apply to me. Apologies for what may appear to be a willfully contrarian post, but I really do take exception to the notion that we need to "retire to something", mainly because that wasn't my experience at all.
Admittedly, I entered retirement via a layoff, so the transition wasn't my choice. However, adjusting to the change was easy. My first day off work felt like a regular day off. So did the second, and the next one, and the next one. It just felt like being off work all the time. Sure, I missed the job and my co-workers, but there was no big existential crisis. I got back into my old hobby of ham radio, and spent the next few years building radio gear. I had never had the time to do it properly before, so I was able to "prove" to myself that I could do it, and do it quite well. I also adopted 3 cats along the way. That was it. When I wasn't building radios and enjoying the company of my kitties, I was riding my bicycle around town. It doesn't take much to fill a day. I also revived and indulged my interest in photography. I never retired to any of these things though. I simply stopped working, and naturally began doing other things. However - and I think this is key - I am not a "doing" person. I don't think I have to be doing something in order to be content or worthy.
Perhaps this is fairly unique to what I think is my rather specific personality type, but isn't simply being alive enough? There are so many wonderful things about simply existing, and experiencing the sights and sounds of our world, that just being alive feels like a great gift to me. One of the nice things about being retired, is that I can go to bed when I want, and get up when I want. A few days ago, I stayed up rather late working on a project. It was still dark when I went to bed, but only just. A few birds were already beginning to get wind of the impending new day. It's quite a wonderful thing to hear them gradually beginning to wake up, before most of the rest of us. This morning, I woke up early, at about 4am, and realized that my little blind kitty was curled up next to my head. As I woke and moved a little, she began quietly purring. It was just her and myself, together in the silence of the night. Such a lovely moment.
If I were still working, I wouldn't have the time to enjoy these, and many, many more moments. And no - I am not one of those new-agey spiritual types who does astrology, has a collection of crystals, and "knows" all sorts of things about my chakras, whatever they might be. I am very much a pragmatist. I just happen to think the world is an endlessly wonderful place, and I like being in it.
I had a girlfriend in college who said, "Tom. There are two types of people. There are do'ers, and be'ers. I think you're a be'er." She had a point. I
do do things - quite a lot of them, in fact. However, I don't feel that I have to do anything in particular in order to justify my existence.
Thanks for listening, and I know that almost no-one here will relate. However, I just gotta be me