Chest tightness and weird heartbeat related to anxiety?

Today while I was driving, all of a sudden my heart beat went from normal to really really slow and really hard.  It hurt my chest really bad and my chest just felt really tight.  It hurt really bad to breathe in and this would last about 1 minute, then go away.  Then about 2 minutes later the same thing would happen again.  It was really scary and it hurt really REALLY bad...i had to pull over on the side of the road and recline my seat.  This has happend to me before too.  I have severe anxiety but today for example, I had no anxiety...my mom said it still could just be from that, but i dont know becuase like i said i have felt no anxiety today! im really worried something might be wrong...or is it normal?

[metalfan1]

Well the last time I went to the ER I had really bad physical symptoms (hot flashes, tremors, felt really cold in the inside and tightness of my jaw) and I hadn't had any anxiety the whole day. But the doctor and the nurses told me that it was anxiety. So I guess it is possible not feel anxiety but still have some physical symptoms. So yes it's normal.