poor you, ive had panic attacks for years and untill you have one you can never understand how awfull they are,
go to your docs for a check up but it sounds like one to me, your doc can help you either tablet or counciling,
avoid caffine and alcohol as this agrivates panic attacks, carry a brown paper bag with you and if you start to feel one sit quietly and breath into bag for a while, i no it's hard but try to stay calm, bach rescue remedy is also good its available at most chemists and health shops,
lots of things can trigger them off, things that we don't even think would at first, there more common than people think, i find i'm more prone to one around my period and if i'm tired or havn't eaten properly, take time out for youself, a nice long soak in the bath then lay down for a while in the qiuet or with soft music.
anyone can get them at any time in there life just keep remembering it will pass and nothing bad will happen to you.
thinking of you x