I remind myself that boredom or ennui is a physical and mental luxury item, and that there is always something that I can do otherwise when I'm feeling that way. Sometimes I just go with the flow of being unmotivated to actually do anything, but I remind myself that it's not something I can afford to do all the time. If I am indulging myself too much in inactivity, it's a time when I may end up having to play the tape forward to recall that drinking to fill my time would be about the worst possible way out of my indifference.
So, I have my structure during the week, and I try to fill in the spaces with some other responsibilities.
You might find that something that sounds too difficult to start as a new project works out in your favor and attends to that down time. But the effort to find it is up to us. It's okay to start something and find that it isn't working, too, and then we ask why?
It's particularly frustrating, I know, when we reach back into the past and find that the interest just isn't there anymore. The spontaneity of feeling joy when we don't expect it is hard to recover when we don't just tip back a bottle and alter our brain chemistry to take us down that lane. Gratitude helps me out of such situations, sometimes.
I see it as part of the recovery of the brain that I just have to attend to the best that I can. As a person with depressive tendencies, I know that it's sometimes just that, and that it will change, something will come forward to pick me up, even if it's just a routine again. We aren't going to feel good all the time.
You'll find what works for you when you are feeling this way.