It often helps to take breaks in between tasks. Taking periodic time-outs help to decrease the level of the stress hormone, cortisol and increases the amount of other chemicals such as dopamine that help us to feel good. Breaks help us become more productive. Allowing yourself to mentally disengage from your work related thoughts for a brief period may help bring in a fresher perspective once you return to the task at hand. Additionally, it may be a good idea to use the break to stretch and walk around. Changes in surrounding also provide a distraction from ruminating on your lack of productivity, and in fact, may provide you the inspiration you were lacking earlier on.