I used to have severe panic attacks, and I have reduced it to a manageable level by following these tips:
a. Muscle relaxation techniques. Everytime when your muscles tensed up, you will shirt all your attention towards relaxing the muscle. The idea here is that you can't be anxious and relaxed at the same time.
b. Get medications from psychiatrist. I was prescribed Xanax in case the attack is too strong to be controlled.
c. Mindfulness. Practice to stay more in the present moment to prevent yourself from dwelling into the past.
If all else fails, consider attending a hypnotherapy session. As KenDowns said, this approach can be used to help you voice out your emotional conflict, and the therapist will decipher what it means.
Hope it helps