I myself suffer from Anxiety. Although the idea of it is really simple, there is a lot we don't know about Anxiety. However, what is known tells us that everyone has something that sets them off. For instance, Open doors , or clocks that make loud ticking noises set me off. Talk to a therapist , or a specialist about it, and maybe they can help.
Please note, The " Doctor" suggesting Lorazepam is trying to push a highly addictive, short acting, short term( normally 2-4 weeks) drug that can cause depression . I have been on it before, and it was one of the worst things a doctor has ever told me to take.