I Have Suffered From Panic Attacks For Many Years. But

I have suffered from panic attacks for many years. But for the last 7 years my symptoms have changed due to some traumatic events in my life. Now, many times in a day, I experience the oncoming of nausea, doom with extreme fear and then a very intense hot flash. Each time this happens it lasts about 2 minutes but I get them throughout the day and night. I have been taking Klonopin for 20 years and an antidepressant (recently Celexa). Please tell me what these horrible symptoms are!