Social anxiety, as well as the other anxiety problems, can be treated.
Your GP should be best to advice you. If your doctor seems to not understand Social Anxiety he is not best for you. In this case I would suggest you seek alternative medical advice. If he doesnt understand the dynamics of Social Anxiety how can he help you overcome it?
It is also possible your doctor mistakes your problem and tries to convince you it might be “just stress” or something similar. In this case you should try to explain in greater detail when and what triggers your “attacks” or alternatively, speak to a councillor. In most cases councillors are aware of psychological problems and have greater experience with people that suffer from anxiety disorders.
As it is still quite an unknown problem, Social Anxiety is not yet a generally accepted disorder and therefore doctors are not always aware of the problems unless they either have known a patient for quite some time or have had encounters with SA before hand. Either way you should not be afraid to tell your doctor.