last year suddenly during sleep i felt burst of pressure in my head for few seconds after a month same pressure i felt during day after that my legs and hands were shaking and my heart was beating fast and i feel tired and lethargic. it is happened for few seconds. it started once in a month now sometimes once in a week and sometimes once or twice a day. please help i visited several doctors but no one is able to find main cause. all MRI and EEG are ok.