Image from PhotoDune
I often lack energy after lunch. I notice it a lot more now that I work from home, compared to when I was surrounded by people in an office.
I once decided not to fight the tiredness, and took a nap. It helped, though I thought I should be conquering my tiredness rather than just giving up. Until I learned that Leonardo da Vinci, Thomas Edison, John D. Rockerfeller and Winston Churchill all energized their creativity and productivity with a daily nap. I had no idea!