Unfinished business

I stepped out of the shower this morning without washing off the soap. A Thought interrrupted the usually-mechanical process. It happens all the time. It's been going on for years and years. It's the same disruptive thought that will one day cause me to step off the kerb and under the wheels of a bus. It's the thought that leads me to scribble things on odd bits of paper wherever I am and whoever I'm with, plus or minus a muttered explanation/apology. It's the thought that has cost me a chunk of money to, so far, no good purpose - a week at Charney Manor to write, a week in the Lake District, ditto. Lately, it has caused me to prevail on my lovely writing group. They've all read the MS for the umpteenth time and given me copious and very helpful notes. I've begun working through them...and stopped. Why? I don't really know, but I suspect it is because I fear I just can't do it. Finish the blasted novel, I mean. On the other hand, I'm too pig-headed to give it up altogether. It's got a mute central character for a start and is set in an unspecified preliterate time and place. Too difficult! I've tried getting him to speak, but he won't. I've now got at least eight versions of it saved and I've all but forgotten where I am. At one point I sent it to my then Hodder editor, Beverley Birch. She thought it was 'a first class idea and potentially a very interesting book...parts of the writing are very effective...use of language outstanding...good creation of atmosphere in general'...but 'it is still not working'. She asked an independent reader to look at it. S/he wasn't convinced by the dialogue or that the past events could cause such distress and disruption. She did like the writing 'lovely and flowing' and thought that 'this writer probably has it in her to write a brilliant book, but at the moment this isn't visible.'  That stopped me writing altogether for a long time.
If there is a plus side, it is that I've fled from it into writing picture books and little short stories for children many times, and some of them have been modestly successful.
It's funny (as in peculiar), this business of not being able to let something go when it isn't serving any useful purpose and is painful and preoccupying. 'You are not a novelist,' I say to myself, sternly. 'Get over it.' Then the little whiny child's voice whimpers back, 'but I WANT TO BE! So there! Boo hoo!'
Is there anyone else out there similarly afflicted? Is there a cure? Anyone know a good shrink? Brain surgeon?