Once you get moving, keep moving. Energy is not something that lives in a bottle and can be taken on a whim . Sometimes you have to force yourself to keep going. Maintaining your momentum increases the chances that you will continue to be productive and finish what you started out to accomplish in the first place, don't fool yourself by telling yourself that you will be able to do it later. This is nothing more than procrastinating and will ultimately leave a lot of unwanted task sitting on the back burner.