Two week before it starts suddenly symptoms were confusion, heartbeat increasing,lightheaded.i had full body checkup and found vitamin d 14.8 and B12 170.4 (which were low), and heart beat was : 43 doc gave me a prescription where there is a B12 dose (Mon & thu in a week,6 times), and vitamin D dose(1 time in a month) i am still struggling with lighthead but the heartbeat increasing problem is gone. Question if vitamin D is too low than B12 what there is only 1 injection dose. what should i do