I would also consider the possibility that you have trouble with heavy metal toxicity. Metals, like mercury and lead, and yeast often seem to go together and, because of this, share a lot of the same frequently-described symptoms.
However, there are people out there who have the problem with metals but don't have yeast in their bodies. They would have some of the commonly-described yeast symptoms, but, of course, an anti-yeast treatment would do nothing to help.