Re vitamin D - I am not a doctor and have no medical training but as far as I am aware there are two forms of vitamin D that can be measured in the blood - 25 hydroxy vitamin D and 1,25 dihydroxy vitamin D.
In general only one form is tested and that is 25 hydroxy which is the major form of the hormone found in the blood.
I understand that in many cases if your standard test for vitamin D levels is low, and you then test the 1,25 dihydroxy levels there is a good chance these will be raised, which indicates inflammation in the body. Where there is inflammation, there is bacteria. Where there is bacteria there is infection. Also, yeast/candida make the inflammation worse so you can have a bacterial and a yeast infection at the same time.
Have you ever been tested for SIBO (small intestinal bacterial overgrowth)?
I also understand that if you have a chronic infection somewhere in your body, then the FMO3 enzyme may be blocked. The FMO3 enzyme is responsible for the odour in TMAU.
It might be worthwhile asking your GP to test your 1,25 dihydroxy levels as a matter of interest, and if they are raised discuss the reasons. If you have never been tested for SIBO, then this is also another avenue you may wish to consider.