I AM HAVING SLEEP DISTURBANCE FOR THE PAST ONE YEAR,MANY DAYS JUST WHEN I START TO SLEEP, I GET TREMOR LIKE VIBRATION IN MY BODY, FALLOWED BY PALPITATION. I SUSPECT THIS COULD BE BRAIN RELATED.FOR THE PAST ONE WEEK I AM ON BETA BLOCKER (5MG AT NIGHT).I AM GLUTEN INTOLERENT.COULD I BE SUFFERING FROM B12 DEFICIENCY, IF SO WHAT TESTS SHOULD I TAKE? PLEASE ADVICE.