My mother went temping when she first went back to work - it got her confidence back and she got to try various different businesses and organisations - apparently admin for the local crem was one of the most interesting.
Don't ignore everything you've done through teaching - it will have given you skills you can use in other jobs, like planning, organising, working to deadlines, thinking on your feet. Can you pin down which bits of it make you feel you weren't good at it? If you can identify that, it might help you avoid it in a future job.
What Colour is My Parachute? is a good book, and might give you ideas. There are various online tools as well, which break things down into specific skills, rather than an overall job - it can be very helpful to work through which things you're really good at and would like to include in a future job, which things you're really not, and really wouldn't want to be a part of a future job (some things may be unavoidable, like every job tends to have an element of routine admin these days, but you could avoid it as a key part of the role) - also, things you're interested in developing, even if you don't have much experience now. There will also be skills you've got from parenting - there's a lot of planning, organising, time-management there, adapting to last minute problems and so on.
When you've worked out that profile of the perfect mix of skills and so on for you, then you can work out what's the best job for you, and whether you need more training or whatever. That may well include nursing, or something else involved in healthcare, but it could also give you other ideas you haven't considered yet.
Good luck!