Just because you're awake doesn't mean you can be productive. People need to have a certain level of energy to do something useful. We also need certain kinds of energy.
Sometimes we're preoccupied with something: getting done chores you're putting off, a conversation you had two weeks ago, that one project you say you're going to work on but still haven't started. When your mind isn't focused, you are not going to get much done. If you try to write, you end up staring at a blank page while your mind races (or wanders). If you try to read, you may discover that you read entire pages and literally retained nothing from it.
If you don't have useful energy, then give up and try again later. Get some sleep, eat a meal, take a walk - do something that will change your mental state.