Could be the issue I just found out I had. Insufficient folate.
B12 and iron did nothing for me and then I found out that too much ferritin and B12 covers up a more serious anemia caused by folate insufficiency.
Folic acid is a chemical poison. Don't take it ever again. Use methyl folate or folinic acid.
I got instant results.
It doesn't solve all the problems. Study the methylation process.