I have panic attacks myself and also think I'm having a heart attack
at times. If your doctor has ruled out any issues, you are probably okay. I have learned to focus my attention on other things and not on the way I feel, it makes it go away. Go pick an arguement with someone and watch how quick your symptoms go away, it's amazing. It's called redirecting your thinking. Go turn on SUPER cold
water and jump in the shower, your symtoms will ease. When you focus your attention on something else, you forget about your back feeling numb or your heart beating to fast or your fingers tingling
. Try it.