Brain fog/derealization for 7 years, still getting worse

It is terrible how brain fog/derealization ruined my life. It happened to me 7 years ago after severe stressful time of my life and it never went away. What is more, it is getting worse and worse in a very strange pattern. Every few months, I have a day, I call "reaching lower low". Just like my brain was reaching lower level of functioning. This day to day change is very visible, like falling from the stairs step. My health problems are: sleep apnea (more precisely UARS), adrenal fatigue (exhaustion), GERD, Hiatal hernia, probably candida, TMJ and other things. For some time I suspected brain tumour, Lyme, but I don't have headaches, vomiting and other signs of them. And I don't want to look for other diseases and add to those I already have. Does anyone have such problems?