Ian
Three pieces of advice (and, yes, I have taken my own advice in the past):
1. Change schools
2. Stick with it
3. Change schools
I know I said change schools twice but it seemed so important I thought I would. If you're not enjoying it, it isn't worth it; if you're not happy with the service you're shelling out thousands for, move; if they charge you a cancellation fee for circumstances outside your control, charge them one for the slots they've cancelled due to weather.
It's horses for courses and I've hated places that others have loved and vice versa. Don't be afraid to move schools. I changed with only the skills test to do and after a thoroughly enjoyable hour at the time I'd booked it, on a beautifully maintained aircraft, I took the skills test on a beautiful, crisp winter's day where you could see forever and enjoyed it and passed.
You can move whenever it suits you, for whatever reason, at whatever stage. Be honest with the new school and you'll find the joy that you've lost will return.
Stick with it, it's worth it. It was 21 years 7 months between first taking control of an aircraft and that skills test I mentioned above, so I know what I'm talking about, but that's another story.