@MancMa, newly single in your 50's is not necessarily a bad place to be.
See it as a resurgence, you've got the back half of your life to get on with it.
I'm seeing my 50's as a really positive stage in my life, I'm fit, able and solvent, and there's so much world out there. It's early middle-age.
Yes, we're not 25 any more.
We're neither old nor young, we have a foot in both camps, and that's pretty cool.
Having said that, I love my teen children and have a great relationship with them, I also love my octogenarian parents (one of whom is still climbing mountains, skiing, and has just published what he considers to be his magnum opus).
I've got plans, I feel like I've only just started in some ways.
You are not old and you look great.
Here's to the second act @MancMa.