Obviously, if you have a rational reason to think you have it, go get tested. That's your first step.
Well, what about talking to your doctor about anxiety? if you have irrational fear, this would be the wise choice, no? Anxiety is treatable. I'd start by talking to your GP and they may or may not refer you for further evaluation by a psychiatrist. And a psychologist is an important part of the process. Lifestyle choices can help too such as exercise, eating right, sleeping regularly, relaxation activities such as yota, meditation, deep breathing, etc. So, look at anxiety as the medical problem you REALLY have and treat it just as you would any other--- by aggressively working on it with your doctor. good luck