Your symptoms are not uncommonly due to reactive hypoglycemia.
1. If you can tolerate sugar, as a test try 1 tsp. white Sugar
when you are having a panic attack and see if that makes the panic attack go away. This indicates hypoglycemia.
2. How soon after eating do your panic attacks occur, and what was it that you ate? For example, if your panic attacks happen four hours after you eat, try eating every three hours.
This is a very complex topic. If you do these tests and respond to this post I'll try to follow up with you...