I have the exact same predicament. I have Candida, SIBO, leaky gut and mild Organophosphate, mercury poisoning.
My brain fog is terrible throughout the day and suddenly starts to improve post 8pm. When I do breathing exercises during the day it improves for maybe a couple of minutes, obviously the b exercises are helping increase blood flow, improve organ efficiency etc thus reducing the toxic load for the liver.
Has anyone come up with any good theories as to why this happens and how we can alleviate it as Im sure all of you know "brain fog" is by far the worst symptom and the first thing I need to get sorted before I can carry on with my life.
Any help would be greatly appreciated as I have been like this for nearly 2 years of chronic brain fog.