I feel this way a lot. Honestly, I don't know how to "power through" it. I just try to remind myself that it will gt better. I think my dogs (yeah, I know) help me out a lot, though, because when I'm feeling that way, they get me up and moving and out of my own head. They need me, so I need to get up and get moving. They'll nudge me out of bed on the days I don't think I can do it myself. I think dogs are really great like that.

Though I'm loathe to admit it, exercise helps. Of course, when I feel like my energy reserves are empty it's hard to get to the exercising (the dogs help with this too). My doctor says, "Just do it. Your body wants you to even if you're mind is telling you that's not true." A lot of people say "mind over matter." I think sometimes with bipolar depression, it's really body (matter) over mind.

Best of luck!