Do things in baby steps. When you see at all what you need to do, you are just overwhelming yourself, and this depletes any motivation. So I suggest to set small goals for yourself that are more realistic. Just pick one thing, and set aside everything else. It's no different when you need to organize your house. It's easier to set aside time do one shelf in a closet than doing the whole closet. Finishing small things will help you feel accomplishment, which in turn will help with the motivation.