I had a phase when my special interests lay dormant. It was a time in my 20s when I was recovering from past familial abuse, the few years after I broke off contact with my family of origin. No motivation either, barely enough energy to get through the day. If I had managed to find a therapist I felt comfortable with (I tried first sessions with three who were progressively worse, unfortunately, then gave up), there's no doubt in my mind that I would have been diagnosed with depression.
I took a break from uni for a year, worked just enough to pay my bills and otherwise zoned out and watched a lot of television. If I hadn't needed to earn a living, nothing would have got me out of bed and even as far as the couch on the worst days. What little I did do took monumental effort.
But for me, it was relatively clear what the problem was, and I also had a very understanding and helpful partner who had a good overall idea of when to push me and when to leave me be, who listened endlessly, asked good questions, had workable ideas and didn't expect progress by leaps and bounds, just babysteps (or 'two steps forward, one step back'). My partner had been through something similar, albeit with a therapist who was wonderful, by the sound of it, and whom I would have tried if she hadn't died prematurely in the meantime.
For me, it was very useful to let it run its course - whatever 'it' was, though I think it was basically depression - without pushing too hard. But - I also had a lot of emotional support from someone who 'got it' and a pretty clear idea of where my problems originated. So that sets our situations apart. All the same, I am not sure this is something you can push yourself out of by sheer force of will, or that it would be advisable if you could.
I would venture a guess that what you're doing - watching television, sleeping, killing time - lets your mind rest, and whatever the underlying problem may be in your case, it might well surface sooner or later as a result. Not necessarily fully formed, but some vague idea or notion, at least. So my advise would be to stop feeling bad about not doing much for a while, because that's just going to drain more mental energy.
You probably have some plan or wish for your future, and I wouldn't stop thinking about it in this situation, even it seems ridiculous from where you are now. You don't need to know exactly how to get there, but it can be helpful to have some dreams in the back of your head. They can help to keep you on track with the babysteps when you find the energy to do something, once in a while.
Regarding energy, I also often say in everyday life that I have 'low energy', even though that isn't strictly true. My energy levels are perfectly fine, the problem is that so much of it goes into the conscious effort of giving a close enough impression of an NT, mostly on the job, and into doing a job that could barely interest me less. (I nonetheless advocate working,
where possible as per one's own judgment, for the sake of one's autonomy and self-direction.) Pacing myself so that there's enough energy left to do what I actually want to do is an ongoing struggle. A lot of it involves boundary-setting, and otherwise knowing when not to pretend too hard because, frankly, some NTs need to not be such delicate mimosas, either, with regard to their social expectations in both amount and conduct. Because contrary to how it is often phrased in common discourse about austism, it's my planet, too. I'm not a mere guest here. All the same, I have enough days when I come home and basically just collapse on the sofa, even though I work half-days in the comparatively dreamy conditions of my own office. Perhaps there's some energy drain in your life, too, that you could actively try to manage to some degree, so it doesn't drain you of your last drop of energy
all the time?
What motivates me, as I hinted above: my dreams. My dreams are things I want to do / be able to do someday, personally or professionally. All my lifelong interests are tied to my dreams in some way, although, as I really began to recover from what I think was depression, I developed some unrelated interests that also take up some time and headspace but aren't quite as fierce.
I have always allowed myself to keep my dreams even when it seemed utterly ridiculous in light of where I actually was. I have had enough positive experiences, successes and achievements (and I don't mean only of the recognised, formal variety, but by my own standards) to know that I might be capable of achieving them. Perhaps not exactly as I picture them, but what reality ever ends up matching a mental picture 100 percent? I have had to remove myself from other people's schedules of how life is supposed to be lived in order to keep working towards my dreams/goals. You know: do a by time b, x by time y? If you are on the autism spectrum, this is actually something that you might find easy. Other people will, of course, have opinions about it, but they'll have opinions either way, and it's your life, not theirs.
Anyway, I hope there's something helpful in that novel.
I wish you the best.
