Hi Charlie04,
It's hard to answer this question, not knowing where you are located.
I'd suggest looking at the list of GPs who specialise in mental illness available on Beyondblue's website. Make an appointment, I'm assuming this is either for yourself or a child? From the GP appointment it would be worthwhile seeking a referral to a Psychologist or Counsellor who specialise in this form of anxiety in teens. You may also find some of the resources for young people on Beyondblue's website helpful.
AGrace
