Congratulations on a successful life and retirement. I recently retired and I was fearful like you as I had worked since I was 16, even worked through college. I initially did a lot of volunteer work, yoga, zumba, etc. as I made the adjustment to having more time on my hands. I've since dropped some of those activities and found that I'm just fine with having 'loose' time on my hands.

Even now, though, I make a list each evening of a few things I want/need to do the next day and I check it in the morning. I rest better knowing I have a daily plan of some sort. I have several hobbies (making jewelry, genealogy, crochet, reading) which help fill my time at home.

If you don't like retirement, though, there are plenty of part-time jobs you could consider. Give yourself permission to create the retirement life you want and to tweak it when/if it isn't working for you. Enjoy.