A useful resource may be my book called "EMDR" (published by BasicBooks). It details several cases of panic, anxiety, and adolescent treatment. The paperback is available through amazon.com
If you decide to try EMDR, it is important that you find a clinician who is adequately trained and familiar with your child's problems. You can access a list of referrals through www.emdr.com
Before you make any decisions, I suggest you discuss your concerns with your present therapist. Perhaps more thorough feedback is necessary. Certainly it is important to intervene before there are further academic problems.