I struggle with fluctuating energy levels. When my energy level is good I can excel. When my energy dips, I have to put a lot more work than the average person

I struggle with fluctuating energy levels. When my energy level is good I can excel. When my energy dips, I have to put a lot more work than the average person to keep moving forward (or even stay awake). When I was younger I had an overly optimistic attitude. I'd end up planning a lot during a phase of high energy only for the gas tank to empty. On days/weeks/months with low energy, it led to a lot of stress.