That is a tough one, it is one I also struggle with. I've found that if I think less, I do more. I tend to think too much about what I need to do, and it creates a deeper feeling of just not wanting to do it. So when I catch myself starting to think, I instead just force myself on my feet, and make myself start something. I also found that if you do one accomplishment, its easier to do other things. Like sometimes I'll go for a short run, and after that I feel more uplifted and ready to do more things. Or if I start a painting, I feel like I accomplished something and it makes me want to do more. So maybe try starting with small things.

I can totally understand. Advice from my psychologist was just do something for 5 minutes Then be kind to yourself that you did do one thing even if it was just a small thing.
If you have to rest for whatever length of time, then do something else 5 minutes. I know this may sound as not very helpful. I personally can say that in my current depressive episode, I have difficulty in getting up for the 5 minutes sometimes. I just have to push myself and say that I can do it.
Hope this helps.