Around 7 years ago I started having several paresthesia attacks. It started with a tingling, numbness on the left side of my scalp and traveled to my left jaw line. These were annoying, but I had a few black outs and went to see my doctor. His initial thought was MS. MRI and blood work all came back fine. I continued to have little annoying "flare ups", but they were never real bothersome until last November. It started with the tingling on the left side of my scalp and a burning sensation at the top of my back. I then started having problems with my vision, mental confussion, headaches, pressure on my chest, extreme fatigue and general weakness on my left side. My doctor again suspected MS. The MRI was fine, blood work came back that I was b12 deficient, large red blood cells and my cholesterol was high (yearly checks were always perfect). I started b12 injections in January, but my fatigue got worse and I had constant vertigo with any movement of my head or eyes. The vertigo went away for about 2 months, but reared its ugly head again about 2 weeks after my last shot. I couldn't get off the couch for 4 days and even lying still didn't help much. My speach is slurring and I am having difficulty finding the right words. I have to use a cane to steady myself, get tired very easy and "spaced out" is not even close to describe me now. It feels like I am high on something. I take syntest(HRT) and advil(for the headaches). I am otherwise a healthy 46 year old female 5'4" 125#. Could it be that I am alergic to the b12? Or is there possibly some other explanation. Thank You in advance.