What gives is your intense fear of breast Cancer or actually having to come to terms that you may lose your breast.
The reason you didn't "freak out" about your "thoracic aneurysm" is you didn't know you had that medical condition and it was tooken care of immediately. You didn't really have much time to think about it.
The things you worry about the most will trigger anxiety or panic attacks even though there is no basis for the phobia.
As for blood pressure? Monitor it if it's high! I was nervous as hell going to see my doc and I clocked in at 160/100 at the first initial reading. It dropped to 128/90 before I left and I'm not some old geezeer either!