are you taking any type of magnesium at the moment?

I take 2 tablets of amino acid chelated magnesium each day (equiv. of 100mg elemental magnesium x 2 - one in the morning and one at night). If I don't take it, I get tightness of the chest. I also have b12 related tingles of the back and it feels like paralysis. Everyone's b12 symptoms are different. Do not take oxide magnesium.

Some people after starting b12 get low in potassium because the body is using up all of the potassium stores to repair itself. The symptoms of that are arhythmia, feeling like you might faint, dizzyness etc. That happened to be 3 days after starting b12.

Even if you've read otherwise, vegetarians are really likely to be low in B12. I don't think you can get b12 from the dirt in vegetables. But people who eat meat can still be low in b12. But it's just something you will have to keep an eye if you are not going to eat meat.

B12 takes a while to heal itself. Your level of 127 is really low, and it will take time for your body to heal itself and also to get your reserves up. You are flooding your body with b12, but it takes time to repair the damage.

MS is usually ruled out by an MRI scan of the brain. Are you also able to get a spinal scan too? Sometimes, in less than 10% of cases, people are diagnosed with MS without brain lesions (by getting a spinal tap, for example), but those are rare. Your symptoms really sound like b12 deficiency to me, but it's important to rule out MS too.

I've been to the emergency department too. Most drs, especially at emergency really don't know what to do. I've been told that I have a mental problem or I'm anxious, but it's the lack of b12 that is making me anxious. Drs don't understand that. They try to cure you as quickly as possible even if the diagnosis is wrong. You have to take charge of your own health.

Try to get a copy of the book "Could it be B12?" by Sally Pacholok. It has lot of stories similar to yours.