your hair analysis showed high mercury levels? is that correct? if so that is surprising if you've never had any mercury fillings. perhaps you might want to look into IP6 as a heavy metal chelator. its gentle and effective.
as for B5, you can experiment with it. i have taken up to 1,000 mg in a day and only felt better for it. just be sure to keep taking the b complex along with it. B5 is cheap.