What Causes Heart Palpitations, Shortness Of Breath And Impaired Vision?

Hi, for the past few weeks, I have been having palpitations, short of breath. A week ago I had The same symptoms at work, my vison went I felt sick and just fainted. I ended up hitting my head on a hard object and then hit my head on the floor, I was out for a few seconds, and my head is still sore, and uncomfortable? What should I do