I was prescribed folate tablets for 4 months roughly 3 years ago. I had blood test 15 months ago which the doctor said checked for low B12 levels and it was ok. The last year has been uttterly awful both physically and mentally and I feel exhausted and fatigued all the time, have got depressed as well. Could the levels have dropped in this time? My doctor says not and doesn't think it is worth testing again.