Hello and welcome to e health forum.
It seems that you may be having excessive anxiety issues. Your symptoms of palpitations are most likely due to anxiety related issues, rather than that of severe cardiac diseases.
You might consult with your doctor for a examination, which will help you clear your doubts about your health concerns.
In addition, consultation with a psychiatrist will also help you to manage your stress and anxiety effectively. This in turn will help you live and enjoy your life.