I haven't been doing so well lately. How are you doing?

Vitamin B12 shouldn't cause adverse side effects, unless perhaps your body is very starved for it and you are very anemic, in which case you might go into overdrive making new red blood cells after you take the B12. I take a B12 2,000 mcg sublingual tablet a day in addition to the B12 in my B complex supplement and what is in my diet. If you are anemic, it is a good idea to take folic acid, iron, and vitamin c as well.

Parasites and/or candida overgrowth can greatly decrease B12 absorption from the gut. That is why sublingual(dissolving under the tongue) or nasal B12 can be very helpful.