Wow, this and playinbout's post is almost exactly how I've felt since I was a kid. I just went on a walk and I didn't feel like I was fully in my body; I felt vaguely disconnected. This constant brain fog causes a lot of anxiety for me whenever I'm out or talking to people, and it's really holding me back in life. My gut feeling is it's caused by my diet/some sort of food allergy and a toxic body.
My plan is to continue improving my diet, short-term fasts, and different cleanses, including cleanses specifically for the liver and kidneys. If I don't get good results I might try something for parasites.