This can easily be caused by certain parasites. They cause problems to the immune-system which results in the over-growth of specific bacteria at different times. The immune-system is constantly playing catch-up. It can also cause yeast problems simply by up-setting bacteria populations.
You mentioned weight loss. This is a common sign of parasitic infection. There may also be issues of hormonal imbalaces sometimes.
I would highly recommend going into anti-parasitic herbs and see the results.
What are your worst symptoms besides those discussed---skin issues, ect.
What was your response to Antibiotics ? Shroom