Hi Sue - you are a champion Mum. It sure sounds like you need a short break away so that you can endure the rest of the journey with renewed vigor. Easier said than done but you have to look at the bigger picture!
If Nat's improving with the exercise and treatment for cording then driving the car should be a task that she can do. Not to all appointments, but say to exercise. You've become her security blanket. I think she is so used to you driving her emotionally and physically that you need to find a way to turn the table slightly so that she is a little more independent.
As Jel said "we have to take care of ourselves if we are to take care of others".
Sending you a virtual hug, take care from Christine xx
