Ever heard of the tale of the two lumberjacks who were tasked with cutting twenty sturdy trees each? One went straight to it, willing to work nonstop until the last trunk fell to the ground. The other made sure that his axe stayed sharp, and he sat down to hone its edges every hour. At the end of the day, the first had cut twelve trees. He was exhausted, his arms swollen and his axe useless. The other had cut all twenty trees, and his axe was sharp enough to do the job of his colleague.
You are the same. Keep yourself sharp by taking breaks when you need them. Breaks protect your physical and mental health, they keep you motivated, they allow you to take better decisions, learn more, remember more, achieve more. Quality breaks make all the difference, so, when in doubt, take a good breath… er.