Feeling stress is the mental equivalent of feeling tired after physical activity, such as running or lifting weights. One more rep when working out breaks your muscles, but allows you to come back stronger. Similarly, one more hour of work when you’re feeling stressed breaks your mind, but allows you to come back stronger.
That crash is a sign that you are hitting up against a wall. Hitting a wall enough times is the only way to break through that wall. So don’t back down when you’re sleepy, hungry, or stressed out. Keep pushing until you crash, because that’s how you make it to the next level. That’s how you make progress.
No one said success would come easy. Fight on.