I have burnt out. I'll tell you what I know. You have a certain amount of energy. It recharges slowly. Just like a battery it can run a milk float for a day or a racing car for 30 seconds. You choose. You can recharge the milk float overnight, the racing car will need it every few minutes. Humans can draw on a reserve battery, but that takes much longer to recharge. Now look at the problem in front of you. Work 24/7 for a week and take a holiday after. Work at a fair pace and reasonable hours and do it until you are 80. Up to you