Welcome to NeuroTalk.

I'd ask you to go back to July and think what you were doing then?

Did you have a virus? Did you take RX drugs for anything? Antibiotics, Cholesterol lowering drugs?

Were you exposed to anything in your home or work?

B12 is only one player in nerve maintenance. Omega-3's are also involved. Also B6 and folate. If you have the MTHFR mutation you won't be methylating folic acid properly either. So methylfolate should be on your supplement list.

You might have to look to your diet... do a trial of gluten free to see if gluten is triggering you. There are other foods to think about...like the nightshade family, dairy, etc.

Do you consume alot of restaurant food? MSG is a powerful trigger in restaurant foods. Sugar consumption? Cutting back severely on sugar and high glycemic foods like white bread, rice, may help.

Have you had your Vit D tested? Low D is very common these days and needs addressing.

These are some starting points.

Can you share with us exactly and how much you are taking of other supplements?