someone tell me what is wrong with me PLEASE

Three days ago i had a very scarry experience.  I was driving to work and i had a spasm, or flutter that started in the left side of my chest, and traveled to my troat.  It only lasted a few seconds, but it felt like eternity, i almost blocked out.  After that i was fine.  

This is not the first time it's happened to me, i have had holter test done, ekg and everything comes out normal.  if anyone has experience the same thing, please, please just let me know that i am not crazy.