Could Experiencing Difficulty In Concentration, Nausea And Painful Chest Be Signs Of Heart Attack?

I think I may have experienced a heart attack but I don't know if it will do any good to go see a doctor now, three days later. I had exercised and found myself short of breathe and with severe chest pains, unable to breath. I had difficulty sleeping and when I had awoken the next morning, I could not get focused I felt unable to function. I went to bed and got up several times throughout the day just after. I have been experiencing some pain in my chest off and on for the past three days and am experiencing difficulty concentrating. If I go to the doctor now, will the doctor be able to diagnose my condition if it was a heart attack? I almost feel as if I have had the flu, but I am not experiencing nausea,