What might cause high b12 levels? i also had low iron (long-standing anemia) and low vitamin d. cbc was normal except mildly low hemoglobin.

B12 normal range: There is no harm in an elevated B12 level. The normal range is established based on a population study, but the physiology and diet factors that might lead to higher levels than those in the population study are not significant. Don't worry about it in the least. Get follow-up to see that the hemoglobin comes back to normal though.