First it starts with the heart racing, then the cold tinglies all over, then it feels like someone is pouring cold water directly on my brain, then the sweats, the shakes and the terror that I cannot escape and that this will never end.
I do know that it will end but at the time of the attack, it sure doesn't feel like it.
I try to keep breathing (as they usually happen while I am driving and I don't want to pass out and kill someone, another terror of mine).
These attacks last anywhere from a few seconds to several hours, which is not fun, when they happen for that long, I just keep breathing and attempt to focus on that, eventually, I do have to leave where I am or the attack will last even longer.
I know panic attacks aren't supposed to last for more than 10 to 20 minutes but mine do, I don't know why and my GP just passes them off as nothing.
Just remembering that there is someone out there who has felt what you are feeling and that I am not the only person who has these attacks helps a bit. Not completely but a bit.