I retired in December, and my DH retired last May. He had an easier transition than I did. He finished the year, so he had closure of the year. He said it just felt like he was on a summer vacation that didn’t end. My last day was November 30, which was a Tuesday. Then Wednesday I didn’t go to work. I always felt like there was something that I was supposed to be doing. It took me a couple of months to adjust. Fortunately I didn’t have to leave a class mid year. When I made the decision to retire, I asked to be moved to an intervention position so I wouldn’t leave a class behind. They keep asking me if I want to sub or continue in my intervention position. No thanks.
Are you retiring at the end of the year? If so, the transition should be a bit easier. I retired in 2019 and have a few friends that just retired last year. I started cleaning up my files and classroom as we completed a unit or a holiday past.