Try positive affirmations. At first when i started using then I felt silly, but they really do work after a while. When I feel panic coming on i say things like 'i am safe, nothing bad is going to happen to me', or 'this will pass soon, it is just adrenaline', or 'by taking this step now, i'll eventually be able to do what I want'.
And every day I try to say general positive affirmations like 'i am confident in myself and those around me', 'i am loved by myself' and 'i am confident in my ability to get better'.
They sound stupid at first, but i think the message really gets through if you keep saying them to yourself!