I'd accepted the 3am wake-up as part of getting older. Two weeks in and it stopped. No tossing, no lying there doing the math on how many hours I had left. First thing in twenty years that has actually worked for me.
You have more time now, not less. Grandkids, travel, the golf course, the projects you put off for thirty years. You want the energy to actually be there for all of it. So the worry stops being about tomorrow morning. It becomes about the next ten years.