When I first had a panic attack 7 years ago I'd never even heard of them or new they existed. I felt pins & needles rush through my face and I felt really dizzy and scared. That happened while I was in an interview, it was awful I started pulling pieces of paper towards me on the desk I was being interviewed at to take the attention away from what was happening, I felt really embarrassed I didn't know what to say so I said Oh man Ive just got a really bad headache and she looked at me stupid, so I said I felt dizzy and she got me some water. I got the job though but every time I saw her I felt so embarrassed. After that first one though I started getting them quite regular I thought they would never go but they did eventually! The first panic attack felt different to the rest just strange like what the hell was that but after that one I always felt the fight or flight when I started getting them, I just felt this ernormous fear like I had to get out of there but everyones feel different I even felt like I was being sucked into the sky on a few occassions...very scary feeling, I seriously thought I was losin it at the time but it is normal lots of people get them and they do go! But you have to ride through each one to overcome it... hiding and avoidance won't work!
I'm not sure If I have panic attacks, but if I'm ever expecting to have an unavoidable interaction with someone, then sometimes I have a feeling of fear that often snowballs.
Once a boss at work started a conversation with me unexpectedley. I answered her question and she gestured for me to elaborate. My fear began snowballing. My heart raced like mad, I felt heat in my face and eventually I had to just tell her I really didn't feel like talking at that moment.
There have been other times where I've been fighting the snowball effect to the point where there's a 50/50 chance of me fleeing.
Dunno if these are classed as panic attacks. I think it's just my fight/flight responses kicking in irrationally.
It's basicly your fight or flight response like beany said. Your body senses a percieved danger so your adrenaline rises and when your not in a situation where your being chased by a tiger or an axe murderer then you don't need all of that adrenaline, so your hearst starts to beat fast, you get hot/sweaty, black out. For me I usually only get them when I smoke weed and just start thinking too much. My heart starts to race really fast and I get paranoid/scared about everything and everyone.