I feel very similar and have had similar experiences--long PhD with just one paper coming out, academia, start-ups, etc. Total lack of motivation. Feeling hopeless and disengaged with everything. My mind is totally not on my work. I have tasks that have dragged for months, projects that are stalling for absolutely no reason, papers that are half-written and now just sitting there. I'm snowed under with work and a lot of it I just don't know how to do at all, like suddenly being in charge of the administration of a bunch of Linux workstations. I've never been good with system administration tasks and have been super stressed out about it--but refusing to just sit down and watch a 20 hour tutorial on Linux administration (mostly because it's hard finding a good one at the right level of difficulty).

In the mornings, when I can stand it, I make a list of all the tasks I want to get done for the day. I never succeed, but at least that gives me a bit of focus and if I cross out a few everyday, I seem to make some progress. But for instance, we're writing a paper that requires a figure from me. That figure required some coding, which I did. Now the results from that coding need another program, this one a graphical one to make a special kind of plot. Last week I was really focused on getting it done and at least completed the first step. But yesterday (Monday), while vaguely thinking about work but refusing to actually work on anything, I *remembered* that the figure was still pending. And I just had this shocked feeling of--wow, I totally forgot that was going on. That whole task/project just evaporated from my mind, even though I was working pretty hard on it less than a week ago. I guess on account of my total lack of engagement... Then I start worrying what other half-done tasks am I forgetting about. I sometimes make a project list, just to try to keep the big picture in order.

Sometimes I try to build myself up by reminding myself that it was always my dream to be a scientist and that my work is interesting and potentially impactful. Or else, I tell myself that I just need to compartmentalize--do my best on my work during the day and let myself be happy doing what I enjoy (writing) in the evening. Sometimes I try to focus on the future--imagining the results of some of my work, how maybe we'll finish the product and actually start selling and it will be exciting. But actually too much future-imagining has been bad for me and I no longer can really derive any feelings of hope from it. I'm actually sick of living for the future. Sometimes I list the tasks I'm stressed out about and instead of just leaving them like that, I try to list all the "problems" with them--what exactly is stressing me out. And then I try to come up with a solution. For instance, the Linux situation is stressing me out less because I did find some online resources to study in my spare time and also found 2 people willing to answer my questions from time to time. That made a huge difference.