If I could recommend a book that I have found very useful:

My Anxious Mind: A Teen's Guide to Managing Anxiety and Panic: Michael A. Tompkins, Katherine A. Martinez, Michael Sloan: 9781433804502: Amazon.com: Books

This book is directed at teenagers, and so parts would not be relevant for you. The book is, however, clear throughout and I really like the explanation of panic attacks and how to deal with them. That is a whole chapter in the book. Maybe check it out and see what you think!