Abnormal blood test results?

After having a blood test to try and find out why I have been so tired and not 'myself.' I received the following test results and have been prescribed 4 months of Folic acid tablets: Serum vitamin B12 level (XE2pf) 270 ng/L [211 - 911) Serum ferritin level (XE24r) 24 ng/ml [10 - 322] Serum folate level (42U5.) 2.3 ng/ml [5.4 - 24] I have not been able to get an appointment to discuss results but need to have an idea as to why they are abnormal. Thank you Maria