I am not familiar with the Andreas Flush, I think most folk on this forum stick to Hulda Clark es method (see this forum for her method steps).
The HC method emphasises use of Epsom Salts (4 X three quater cups, two the evening before and two the next morning). The intestines do not take kindly to Epsom Salts and expell this just a rapidly as it can - like you get raging diahorrea the morning after if not in the middle of the night.
I feel for your frustration in not being well. Please be sure of what you are trying to achieve, if you stir up the liver and get lots of bile release by taking oil, you must then get rid of that bile at speed, otherwise you get reabsobtion and toxins circulating in your blood until your liver can put them out of harms way again.
Brain Fog indicates toxins in the blood system, which is what is probably making you feel so bad.
While Liver Cleanse is an excellent treatment, total good health comes from additional other sources. Personally I think there are few things better than getting a good quality juice machine and getting serious about juicing, particularly from a wide range of vegetables. This then provides excellent nutrition to allow your body to recover and do what it is supposed to do. There are liver support nutrient suplements which are also worth thinking about.