K.J.
Reading your description sent bells going off in my head. My 16 year old son recently had a few episodes like yours. Like you, he was resting when these things happened. My concern was his heart, he was born with a mild heart murmur, and although I am trained in the med field, I listened to his heart and heard no murmur, I still took him to the doctor. They told him the same thing, panic attacks. The doctor even appeased me with my concerns for his heart by putting him on a 24 hour heart monitor. But, the results were still, panic attacks and meds recommended. I told them NO meds for my kid! No way. He is too young, and there has been way too much go wrong with that stuff.
I have begun to believe that those drugs are what they use when they cannot figure it out.
So.. on to help you... Son and I looked at what he had been eating/drinking prior to these attacks. The common thread we found was caffeine and high sugar intakes. So, no more caffeine for him, and we drastically reduced his sugars, including processed foods. He has not had an attack since.
One thing he was drinking that was sorta a 'sneaky' caffeine in my mind was those Monster and Jolt type energy drinks.
My advice is to take a long hard look at your diet. Everything you put in your mouth. Try to go as natural, organic and fresh as possible. I know it is expensive, but your life is priceless! It would probably have added benefits in your families health too. Best of luck to you!