Good evening @judithh580, First, I am glad your TKR site is only minimally painful. Until I read that I was going to suggest a knee icepack. However, good for you.....to be on your way to recovery. So here are a couple of other ideas for you to think about:
1. Meditation......focus on "breathing in" and then "breathing out". You can also find a 10-minute nighttime meditation on "CALM".
2. Nighttime CBD/THC as in a 2:1 CBD/THC tincture. Half of a dropper might do the trick. And the nice thing is that you will be able to stay asleep till morning.
3. Make sure you are not drinking something with caffeine in it any time after about 8 pm. I love "UPTIME " sugar-free beverages. However, I can't drink them in
the evening because they do have natural caffeine and it will keep me awake
4. Try not to watch or read about unsettling news at or near your bedtime. There seems to be a lot of it these days.

Hope one of those ideas might be helpful.
May you be safe, protected and free of inner and outer pain.
Chris