@lgrec Can you explain how you concluded that your symptoms are caused by low brain energy and not the histamine release and symptoms of the allergies or the actual physical effect of exhaustion?

Have you confirmed that you are adequately hydrated, maintaining good nutrition and getting adequate restful sleep? These are the basics that help maintain our health even when under stress.
And for those who suffer from seasonal allergies, there are many choices of non-sedating medications that not only relieve the symptoms, but block the histamine overload that can cause the "fog" you describe.

If you suffer symptoms frequently, maybe you can get a thorough physical, with complete bloodwork, to determine whether you have any correctable vitamin or mineral deficiencies or unknow health problems.