Retirement is a whole different mindset.
At first, you seem lost like a ship without a rudder, wandering aimlessly. There's no longer that purpose of showing up at work and the accomplishment of the challenges you meet there. There's also a bit of isolation, because you are used to being around all those people at work, lunches with co-workers, etc. You have to find new purposes and boot yourself out of the house to find people to interrelate with. It takes a little while.
You think you'll have all the time in the world free to do what you wish, but it is exactly the opposite. It seems that your days are so filled that you wonder when you ever had time to work. Also, I find that I am less efficient in my scheduling than I used to be. When I was working, I got off at 3:15 and I could make 2 or three stops on the way home before businesses closed at 5:00pm. Now, I will rise in the morning (much later than the sun) and I will think to myself, I can't really do anything, because I have a dental appointment today -- at 2pm. What's with that?
I am a member of three quilt guilds and a hand quilting group that meets weekly. I sew quilts top and I also have a longarm on which I do my own quilts and a few for others. I have a part time job (2 days a week, sometimes 2 1/2). I read a lot and I have the usual appointments and errands like grocery shopping. That doesn't sound like much, but I never seem to have any time.
I think it is just the retirement mindset. I have also become much more of a procrastinator, especially when there are things that I don't want to do. I will think to myself "I'm retired, I don't have to do that at any special time".