Vitamin B deficiency is quite serious and can cause all sorts of medical problems, including symptoms of what I have which is Myasthenia gravis. Find a doctor who can help with Vitamin deficiencies. This is important and will most likely help with your symptoms.

I have read somewhere, but can't remember where, that taking vitamin B pills works better that the shot. Try taking Vitamin B Complex pills daily. Since the shots help for 4 days I think daily vitamins should help even more.

I hope you are feeling better.