This may come as no surprise to some, but just recently I've noticed that my energy fluctuations, over an entire year, move in sync with the sun. My energy runs pretty high in May and June, right before the longest day of the year (Summer Solstice--June 21). It runs high again in September, I'm guessing because after the hot summer some cooling breezes refresh me. Then, in October & November, my energy steadily decreases, as the days get shorter and shorter. Right after the Winter Solstice (around December 21, the shortest and darkest day of the year) comes the Christmas holidays. Then, in January, as the days start getting longer and longer again, I have another energy surge. This wanes again in February, but once warm weather starts coming in March & April, my energy has momentary lifts and increases until it hits a high in May and/or June again.
Now that it's July and very hot, I'm lagging a bit again.
So, knowing this, I can take advantage of it. Heavy gardening work should be undertaken in the Spring and Fall. July and August should be spent resting, reading, studying, working on my own personal projects, planning for the upcoming homeschool year, Christmas gift planning, etc. (In other words, sit-down tasks.)
Besides gardening, in September I should do all of my Christmas shopping, etc. Then I can just enjoy the Fall months homeschooling and prepping for the various holidays at a slow, steady pace. By the time I have the least energy, I can just glide through Christmas as all the energetic work will already be done.
January's energy is good for getting a good start on those New Year's Resolutions (yes, I set goals every year). If I'm smart, I'll also do some gardening now (making plans, ordering seeds, cleaning and sharpening garden tools, etc.). Then I can just push my way through to the end of the school year, and I'm ready to jump into the May and June gardening again!