On the days when you feel exhausted, give yourself a lot of time to rest mentally. Perhaps you have a lot to do and it is not possible for you to lay down and rest at all during your day, but you can always give yourself a moment here and there where you rest mentally. That is just as beneficial.
Take a moment to close your eyes, take a few deep breaths and listen to the soothing stillness within. Stay in this comforting place of ease for a minute or two and allow your body to relax. Then, gently open your eyes, smile and thank your body for this relaxing moment.
As you move on with your day do so with the intention of being extra kind, loving and gentle with yourself.