Like at that moment, how am I suppose to know it's a heart attack? What do I do to help?

Fight. Against it. Be calm down. Don't panic. Deep brathe.

i've never suffered from one myself, but my grandad has had two. He thought it was indigestion (apparently the feeling is very similar) but then it happened again 3 weeks later, and he was taken into intensive care :S The doc said it's a feeling that you'll have never had before, and if you've had one, then it's clear you'll know if it happens again. hope that helps Ooh.. and if you think you're having one right now then I'd suggest you ring an ambulance straight away because it could be serious. in the meantime, just try to keep calm and breathe.