I definitely agree with those who suggested finding a therapist who specializes in, or at least has experience in gender issues, if at all possible. The Psychology Today site mentioned earlier is a good resource. My therapist has such a background and she is very affirming and supportive.
Also, my cardiologist read me the same riot act and, in addition to starting therapy, I have also begun attending some very mellow yoga classes. Great stress relief.
Best of luck and know that we are all pulling for you!