I agree it could be a sign of depression, but it could also be other things.
I've been consistently bored silly with pretty much everything I'm doing, for a few months now. Don't know why, or how to fix it. Could just be a matter of my high boredom threshold running out of exciting things to do......I never feel quite right unless I'm pushing the envelope and making at least some headway in an area in which I was hitherto powerless, but sometimes I just don't see any new envelopes that seem worth pushing.
I've also seen how a lot of my life has been wasted in doing things the long way round. I think that's given me a reluctance to get too involved in anything big, in case I waste any more time.
Certainly the perceived level of difficulty comes into it.....when I'm wondering what to do, I often catch myself thinking "nah" very glibly, I don't want to get stuck with a project that isn't going anywhere. I've tried self-discipline but I just drift back into the same state.
If it weren't for promises I make to friends, I'd probably never get off my butt. I have a morbid fear of letting people down, which keeps me motivated, though I wish my motivations could be more positive than that.
I don't think these cold, dark winter days make things any easier....can't afford to heat the entire house so I get stuck in the only warm room. At least the daylight's coming back at last - it's no longer dark when I go home from work, though it's still dark by the time I've got back into the house.