Another is when absolutely everything seems like just exactly too much effort to bother doing, and/or nothing seems important.
There's at least one brain chemical involved, that somehow seems to directly reflect the aggregate amount of [how much we've done to take care of ourselves]. That's why my recipe for climbing out of depressive moods is a laundry list of routine self-care tasks like sleeping, eating, bathing, and so on. You just run down the checklist, begrudgingly going through the motions of each self-care task until, for seemingly no reason, you feel OK. If you get to the end of the (long) list and still feel bad, well, then I'll say one is entitled to indulge in feeling bad. At that point further research is required, research which hopefully points to what needs to be done.
Like most of the things I know that can be construed as advice, I often forget to apply this to myself.
cross-posted from another thread