Is it possible to save a (science) PhD in 10 months? In short: I am starting my fourth year of PhD, and my funding is running out in roughly ten months. I could use some advice about how to make the most of the time I have left, in particular to make sure I deliver something coherent and I am employable afterwards. 

More context: 


During the past three years, I have struggled with personal issues (breakup of a long-term relationship due to moving away for the PhD), poor lifestyle choices, and discipline problems, all impacting my PhD research. 
The result: after three years, I still haven't finished writing the manuscript of my main project, a project I don't like at all because it was half-baked since the beginning. What makes it harder to swallow is that I am 100% responsible for this situation. 
My supervisor was understanding at first, and started becoming stricter and stricter over time because of the lack of output. This in turn caused some other problems (stress, loss of sleep). Recently we had a discussion where he told me he would not let me finish my PhD, because otherwise I'd need 10 years to complete it and he can't afford to pay me for such time... 
I reached the point where I am completely disgusted with what I am doing and I am seeking a way out. My only problem is that I'd like to make sure I am employable. So I figured my best bet would be to try completing the PhD, no matter if it is imperfect / incomplete. 
Since I have only ~10 months left (roughly 10 because I could probably survive a few more months with my savings) to make up for the last three years, I'd like some pointers about how to make the most out of it, without going completely insane. To be more specific, I guess I am looking for advice about efficiency (both in professional and personal life), how to be more stable, how to make strategic choices and set priorities when there is a lack of time.
To be honest, from your description I would be less concerned with finishing your PhD and more concerned about your mental health.

You should probably talk to a mental health professional or GP, and then worry about this. The chances that the road to a PhD would be forever closed for you is reasonably small, but if you don't take care of yourself the impacts can be significant.