Hi Kitty. I hate when that happens. SOmetimes, it feels like out of the blue because it's your body reacting to some sort of stimulus without you knowing it - could be a sound, smell, thought, whatever, that triggers the panic reaction in you. I now it helps me to know exactly what is going on in my body to give me those horrible feeloings and makes it easier for me to say "ok, that is just a panic attack, it's just a feeling and it will go away" which makes it much less intense and shorter.
If you just look at the info on this site, I'm sure you'll find it helpful. Here is something i cut and pasted from under "Education - What are panic attacks?" on the left of your screen:
"A panic attack is a brief episode of intense fear and it is usually accompanied by physical symptoms that may include chest pain, heart palpitations, shortness of breath, dizziness, or abdominal distress. In scientific terms, panic attacks are thought to occur when the brain's normal mechanism for reacting to a threat the so-called "fight or flight" response gets "switched on" at the wrong time. Panic attacks usually last for a few minutes but may continue for much longer. Most panic attacks are at their worst between 10 and 30 minutes after they begin. The symptoms usually fade over the course of about an hour.
Usually, a first panic attack seems to come out of the blue. It might happen when you are dong something ordinary like driving a car, shopping, or going to work. Suddenly, you are overwhelmed by frightening and uncomfortable symptoms. Panic attacks usually take a person completely by surprise. One reason they're so devastating is that you cant really predict when theyll happen."