I read your story and hear your suffering mate! If you read my early posts you will find a suffering brother in me. I had the same type of questions so your questions are alright.
I would not jump to hasty conclusions. Keep a cool head and do serious check ups and resurge. I know its hard but I did it that way because I didnt improve on the diet and everything went downhill. My main suffering was brainfog, anexity, panic attacks, and several other sympthoms. I felt like being seasick all the time.
What did I do to feel better. First I had my MD check me for everything possible. After he said you have nothing, I at least knew that I didnt have cancer or something else. Then I questioned if its really candida. You cant simply assume that you have Candida because of the sympthoms. SIBO has the same list of sympthoms.
I read a book about IBS and changed my diet from high fiber to low fiber. And noticed that my brainfog said good bye too me after only 2 days. I continued to feel better and was eating low fibre for a week or two to check and noticed that my diarre stopped. If you have much problems with the stomach it is possible that you suffer from malnutrition and lack of Vitamin B12. The lack of magnesium, B12 and malnutrition can mess up your nerves. Get a B12 spray for the nose as the intestines cant manage the pills.
Now I bought a amazing book with tons of knowleadge and will start to follow her diet.
all the best