I can very much relate to this. I spend quite a bit of time imagining what I could do to myself and making plans but when I try to act on things most of the time I feel too exhausted and like it's too much effort and like I just physically can't take the actions required. It does feel strange, when you want to do something but feel like you can't. Do you do this planning when you're not occupied or when you're trying to sleep etc? I find that having too much head space can lead to it being filled with stuff like that.
Is there anything you enjoy doing that you have the energy and motivation to do?