Er on sunday for lightheadedness, palpitations. heart monitor on monday. ive been relaxing, and decided to go on a walk. noticed my legs were getting heavy jello sensation. possibly shaking cant tell. but weak and heavy. what could be going on?

Weak&heavy legs are nonspecific symptoms. You've only been examined in the emergency room, I recommend seeing a specialist in internal medicine who will take a thorough history & system review, perform a complete physical examination& order appropriate lab work in order to make a differential diagnosis and advise you. You may be referred to another specialist depending upon the assessment.