I just love having a facial. After a really stressful few weeks (including DIL nearly giving birth on my kitchen floor, and a series of son related meetings) I was very tense, so treated myself to a facial. I have a beautician who does home visits, so her rates are far cheaper than they were when she worked in the salon where we first met. Her facial includes a head and neck massage, I hadn't realised quite how tense I was until she started working on me.
I also enjoy boat trips, just sitting watching the world go by, with a nice coffee, doing absolutely nothing.
If you can afford it, go away for a couple of days - look at the LateRooms site, or "book direct rooms".
Soon after I was widowed, I found a book which was aimed at helping life a better life in the future.
While you are on your own, write down a few things that you'd like to do, anything from learn how to knit, to a trip to France. Work out if your day is too full, and then think if there's anything you can do to change this. (Dishwasher, tumble dryer). I found it a really interesting exercise, which helped me realise firstly just how little time and money I ever spent on myself, then how I could tweak things in future. Having my legs waxed, eyebrows done, lashes tinted, and hair coloured regularly at the hairdresser has made me look at least 10 years younger. Having recently turned 60 I applied for my senior citizens discount card at the local garden centre. They didn't belive I was eligible and insisted on asking for proof of age, which made my day!!
You could also go through your wardrobe, chuck out all the old tired stuff and work out what needs replacing, then head off to the High Street. There are some fantastic bargains out there. Be sure to treat yourself to a visit to the coffee shop for something sinful. Hope there's something hear which you might be tempted with.