Tests for magnesium only are useful for very low or very high results. The in between range does not reflect what is IN your cells.

You can try soaking in epsom salt baths....if this helps, it points to needing an oral supplement (oxide form does not work).

Vegetarians also become low in zinc. The phytates in veggies complex zinc out of the food, and prevent absorption.
So a zinc supplement may help. OptiZinc is the easiest to tolerate. Zinc sulfate causes nausea in some people.

Vegetarians also become low in methionine, which composes SAM which is a methyl donor for many body symptoms. Methionine is an amino acid found in animal sourced foods.

Vaccine injuries are becoming more common. They have adjuvants added to them, to stimulate the immune system, and some people have genetic sensitivity to this, and over-react, causing autoimmune reactions. 8-9 vaccines sounds like alot to me!

Also going to India, you could have picked up a parasite. Tapeworms specifically rob B12 that people consume, and hence they become severely low all of a sudden. The eosinophil count in the blood CBC will sometimes be elevated if parasites are present, but not always. Parasites typically have biochemical ways of eluding the immune system and can appear invisible.

The range you were given for your B12 is the old outdated one.
400 is now considered the lowest normal. You may have to take a higher dose (5mg orally methyl B12) for a while to bring up your results. You should be using the methylcobalamin because you don't know (without a specific DNA test) if you can activate (methylate) folic acid and B12 in the body.

Very low B12 can affect the heart. So it is really important to discover what caused your very low level...and fix that. Be it diet, poor methylation ability (MTHFR polymorphism genetic failure), drug use (acid reflux drugs or other specific drugs), genetic inherited pernicious anemia, etc. I am not familiar with your Thalassemia..that I would expect a hematologist to be monitoring (as well and the low B12).

Here is a video just posted here recently on what low B12 can do to a person:
http://www.youtube.com/watch?v=BvEiz...ature=youtu.be

This is my B12 informational thread:
http://neurotalk.psychcentral.com/thread85103.html

It is long, but has many medical links on it so try to read it eventually. The first 10 posts have most of the useful links and the rest is conversation and discussion.

Check out that heart murmur... as mitral valve prolapse can sneak up on a person.