Have you thought about Adrenal fatigue?
I have had similar problems. I went to my doctor because I was having dizzy spells and light spots. I had blood tests and everything was great. Thyroid was normal, cholesterol is near perfect, everything looks “normal” and yet I still have these problems. The good Doc (not and endo doc) said antidepressants... I said no thanks.
I already take B vitamin supplements. So I did research and this site http://www.drrind.com/scorecardmatrix.asp compares thyroid and adrenal symptoms. The more I read and researched adrenal glands more it sounded like me and thyroid and adrenal problems kind of go hand-in-hand. The adrenal glands have to work extra hard to make up for a low functioning thyroid.
There are many supplements you can take to support adrenal function. It may not be what you are experiencing but something I found…..
Did your doctor test for insulin levels?
The range that my lab uses for B12 is 200-1100. Mine was just above 200 also and my doctor started me on shots right away. The original script was: weekly for 3 weeks, then dropped to monthly for a few months, but I had a lot of symptoms after about a week or so, so my doctor let me go to every 2 weeks. I still have symptoms between shots, but my last levels were at 700 so doctor won't let me increase the frequency because it's "normal" (not necessarily for me, but apparently for someone). For the week before I can take another shot I supplement with a sublingual, as Laura suggested. I can certainly sympathize with the way you must feel.
Did you also have your thyroid tested? The main symptoms I had with the B12 deficiency was fatigue and tingling/burning in my hands and feet; I didn't start getting the fog until my thyroid went haywire. That's also when I got the lightheaded, dizziness because my heart rate was very low.
Yes I would definately agree with you....you could start with a B12 sublingual that you dissolve under your tongue. (Use the methylcobalamin) 5,000 mcg daily lozenges are great.
Maybe just maybe you can get your dr to let you do shots for a while. The lab range I have is 211-911. At the 200's level you are probably highly symptomatic and your symptoms are right in line as you said.
Most countries and drs like to see 600 and higher, for some reason our numbers are much lower in the US.