I am confused as to why my GP has told me to stop taking B12... was diagnosed as hyphothyroid around 14 years ago. What is the problem with B12.? I thought hypothyroidism benefited by it. I sleep on average for 2-3 hrs per night and have no energy, anxious and memory loss., convinced I have dementia. Specialists tell me I'm normal. Took 75mcg thyroxine for years, Doc told me to reduce to 50mcg and immediately the weight soared and felt cold and shivery. When on 50 feel cold, when on 75 burning up and perspiring profusely. I feel anything but normal. 71yrs old. Any advice please?