Your post was like a breath of fresh air to me wildrose! 
The main thing is, you sound content, and contentment and lack of stress and pressure is priceless. Like you, I feel slightly guilty that I am wasting my days in retirement. Some days I do very little but read, do puzzles, catch up on TV programmes, mooch in the supermarket, potter in the garden and decide I can't be bothered to cook an evening meal, so have toast instead!
It's lovely being my own boss, and you should relish that too. I think if you've had a work ethic and always been very busy, committed and reliable, switching off from that is hard to do - hence the guilt that life isn't busier or more productive. I made a conscious decision to take my foot off the peddle in retirement. Like you, I retired on health grounds and had to get by on a much smaller income.
I have friends who have timetables on their kitchen wall because they have 'activities' to go to every single day of the week.
One of my friends, recently retired, has even planned her husband's days. He has to go to bowling, whether he wants to or not. He hasn't showed an interest in bowls in all the years I've known him! She goes to pilates one day, has to shop on certain days, do the housework on certain days, goes to the garden centre for coffee on a Wednesday, goes into town on a Thursday....you get the picture. Even weekends have an agenda and she gets up early and is out of the house before 9am most days. (Oh the joy of a leisurely breakfast/morning I say!) I don't understand why her life has to be so regimented, but accept that we are all different.
In retirement I find it hard to motivate myself and tend to be a spur of the moment person. If something takes my fancy I'll make an effort to go, but should it be something that requires regular commitment I tend to shy away from it. Strangely, I have applied to sit on all sorts of committees, which have involved me sending in a CV and having to be interviewed to check my suitability for the post. They are non-remunerated, voluntary positions yet I get a buzz from being involved and from others needing my input. My friends think I am weird, so I suppose 'horses for courses' applies in retirement.
Do your own thing. One of my favourite bits of poetry is "What is life if full of care, we have no time to stand and stare." Retirement is hard to get used to, but I recommend standing and staring sometimes. Life doesn't have to be busy any more. Doing nothing can be extremely rewarding!