I agree that it sounds like depression. If it were just "laziness" then you would have a choice in the matter and accept the consequences... but with depression the fatigue and negativity can be paralyzing and we are no longer "in control" of these symptoms.
But we are still in control in the sense that once we recognize these problems, and realize that we want to change these "habits" but are unable to do so on our own, we can still make the choice to get help. If depression or some other disorder is at the root of your problem then there are lots of treatment options. The disorder is much more understood now as you may know from your experience with your bipolar diagnosis. Medical and therapy options can make a real difference.
I am curious if your "laziness" goes away when you experience a manic episode? I don't have first hand experience with bipolar disorder (my diagnosis is depression) but many of my friends experience not only hyper levels of activity but also a real "go-getter" attitude when they are manic. Which is not to say that your episodes will be the same, as everyone shows their symptoms differently.
Good luck in getting some help with this.
And welcome to the forums here, you will find a lot of understanding and support here.
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