Undermethylation/Histamine the best test?


I took the Histamine and Pyroluria test. I am an UM. So my Naturopath gave me 5 HTP and I have a huge migraine. I remember years ago I had a test and I was high in Serotonin. Which is strange cuz usually under methylators are low in Serotonin. So I'm wondering if this is the best test for methylation. And if there is any other way to determine if I am really an overmethylator. I was convinced by symptoms that i am OM. Maybe I should start taking higher doses of Niacin and see if I tolerate it? I am on a OM protocol for Pyroluria and don't want to be on the wrong one.