Hi, tiredoflyme,
"I also got recent lab tests back which show excessive b12 in my system."
Did you consider this with your 23andme results? Because if you have excessive B12, that could mean you aren't processing it properly. Did you discuss this with your LLMD?
"You can find yourself with high folate or high B12 i.e. your body will have problems converting inactive forms of folate and B12 to the active forms. So the inactive folate or B12 will simply build up in your serum, also inhibiting the active forms. Most serum folate tests are actually measuring folic acid, which needed to be converted to methylfolate to be used metabolically."
www.stopthethyroidmadness.com/mthfr/