Brain fog is caused by inflammation. I know I have had it for two years after a very stressful time as well. Now that I have found the source of inflammation for me it has gotten better. Inflammation is also what is causing all of the adrenaline. Adrenaline is what is released to stop Inflammation. Anyways there can be many sources of inflammation. food allergies , nutritional deficiencies ( I have low feritin Iron and food allergies ) thyroid problems, gut problems, ect. ect. You have to find the source.