Hi,
So i had treated an b12-deficiency and experienced the "worse before better" situation. To make a long story short, this actually turned out to be an induced copper deficiency as my body rapidly started producing new red blood cells to correct the macrocytic anemia. This required increased mobilization of iron from ferritin, which is handled by the copper dependent protein ceruplasmin; thus copper levels dropped.
Might be something to look in to for anyone else that's also having the "worse before better" respons.