I've had "attacks" like the one you describe on and off over the years. I don't know if they're considered panic attacks... the few people I know who have had diagnosed panic attacks described it as very physical. One actually called the police because he thought he was having a heart attack. Mine are physical... I don't like to be around light, I like to have pressure on my head (blankets and pillows), and I get very twitchy... but not as extreme as what I think of as a "panic attack"... but I don't really know.
A few months ago I finally decided that I needed medication for my depression and anxiety, so I'm on Prozac now; that and the sobriety seem to be helping massively so far.
But I also dealt with them med-free for many years. I can describe my process:
Step One. Get myself to the "safest" possible place. Ideally this is home, in my room with the door closed. But if I'm out and about it may be a park or a library or even just locking myself in a bathroom somewhere.
Step Two. STOP the swirling thoughts. I find that the first thing I experience is the physical feeling. Then my brain basically reacts like it's a fire alarm and goes looking for the fire. If I give in to this, I'll latch onto some crazy train of thought and become obsessed with it. "I'm anxious because of that thing that happened yesterday!"
Step Three. Focus on the physical sensations. I remind myself that the thoughts are just my brain reacting to whatever biochemical thing is happening to me, and focus in on those feelings. I mentally scan my body for the places where I feel the anxiety, and examine them the way I would physical pain. I try to feel it just as a sensation, without attaching words or meaning to it.
Step Four. Once I've gotten to that wordless, physical place, I just wait it out. Again, ideally this is at home in bed with the covers over my head! But in a pinch I can do it anywhere... I just need to work harder when I'm out to not let myself obsess over whether or not people are noticing my behavior.
A lot of this approach is based of of things I learned from meditation, which I've practiced since I was young. You might want to try attending some classes... there are free classes offered by many centers everywhere I've ever lived, so maybe some near you too?
A couple links from Luxembourg:
Welcome to the Frontpage Cours de méditation - Urbeez Luxembourg AngloINFO Luxembourg: Pilates, Yoga & Meditation The AngloFILE Business Directory Luxembourg
Anyway, that's what works for me.
Have you been to a doctor about this?