If my body lacks Vitamin B12, what can happen??

If my body lacks Vitamin B12, what can happen??
Its good for energy, a lack of it might make you feel drained.
i'm currently studying the central nervous system pathology. lack of vitamin B12 or cobalamin can cause pernicious anemia, subacute combined degeneration of spinal cord and sometimes megaloblastic madness. megaloblastic madness is a kind of mental confusion state while pernicious anemia is one of the many types of anemia where u'll easly feel tired n lack of energy. the subacute combined degenaration of spinal cord is a more serious ones. it can leads to spasticity, weakness and loss of proprioception - they are considered motor and sensory abnormalities. get a supplement of B12, ok?
the two WORST things can be this:
dementia or mental illness and
nueropothia(sp?)
i have perncious anemia which is caused by lack of B12 absorption in the stomach- I have to take shots
it takes a lot to get to the point where you have to take shots but you will know it cuz you will be very very tired and foggy headed and your extremities will become numb - feet and hands... I thought I have carpal tunnel at first
the good news is that it's very treatable with suppliments or shots