Right, I am now thinking like an (almost) rational person and I realise that my initial reaction was a bit OTT. So after two days scraping paint off my garage floor and trying not to think about flying, I have decided to continue. Here, then, is my plan:
1) Do some solo circuits or a solo navex just to get back in the plane and remind myself that it's fun, as suggested by Whirly, Westwind and others. (Whirly, I loved your line 'So go up there for a fun flight, look at the view, and remind yourself of what the rest of your life could be like.)
2) Book some lessons with a different instructor to get me fully up to speed and ready.
3) Take, and hopefully pass, the rt test and skills test.
4) Go fly!
I think one or two people mentioned earlier that I should take the problem to the CFI. Unfortunately he is the CFI. He is also the examiner for the rt and skills test. So if there are further problems with him then I will have a quiet chat about life with him, and if this does not resolve the situation then I will change schools and take the skills test some place else.
Thanks for all the replies, they have really made a difference. To be honest I thought there would be a lot more people telling me to pull myself together, etc. Unfortunately it seems to be a far from unusual experience and many of you have been there before me, some of you on numerous occasions it seems. That just cannot be right, can it? Oh well, guess I'd better stop now before I go off on one again.
Cheers for now,
Dave.