This is really a continuation of my story. Just to recap, I'm the guy who had IBS for years and had amazing results when taking Zinc and B12 and I'm not on a methylation program. So, I started taking Methylcobalamin partly because of this forum and my understanding of how it's more useable by the body without various stages of metabolisation and I believed this may be good for me with a deficiency. So my 60 day supply run out 3 or 4 days ago, and I thought as a test, I would switch from 5000mcg mcb B12 in the morning and 500mg normal supermarket B12 in the evening TO: 2 x 500mg normal B12 a day. What is immediately apparent with 24 hours is mainly neurological symptoms which had gone when I initially started taking B12, not the Methylcobalamin, but right at the start when I first realised I was short on vitamins, even though I am still taking some B12? Has my body "got used" to those high levels of B12 and is now suffering or is it a genuine proof of some underlying disorder such as low spinal fluid B12? The symptoms which have come back are mainly neurological: anxiety, chronic biting of nails, pulling out hair, lack of confidence, unsteady on feet, unsteady eyes, and really important, the problem I had all my life until B12: "day-dreamy eyes", please make no mistake, this day dreamy eyes is not something I made up, it's a VERY noticeable symptom which affects me. Any help appreciated. The replacement methylcobalamin has been ordered!