MTHFR homozygous and substituting Methylfolate: experiences?

I have been found homozygous for MTHFR C677T by 23andme and have trouble with substitutung Methyl-B12 and Methylfolate. They increase my symptoms very much even after stopping supplementation. However, I'm not sure if it's from the B12 because I have taken both together. I'll try Methyl-B9 alone shortly.

What where your experiences? Did you have trouble substituting Methyl-B12 and/or Methyl-B9? I'm specially interested in people who are MTHFR homozygous like myself.