I don't know how high 13 is in comparison to the norm. There are quizzes for other conditions that could be responsible for your anxiety or psychologists or doctors can try to make a diagnosis if you find this condition debilitating.
In a different light, I might suggest something like Toastmasters where you get up an give a speech and listen to other people give speeches. It teaches listening skills and also helps build confidence when speaking. It is also a more controlled social environment so perhaps less anxiety. This is a more practical take the bull by the horns approach and see if you can wrestle it to the ground. Toastmasters has meetings in many cities throughout the US. Google should tell you how close.