How can I overcome

You need confidence in your nursing knowledge. I went in believing that the instructors taught me the information that I needed to know. I did well on my Comprehensive predictor (99% probability to pass NCLEX) and I did well on Kaplan review q bank and trainers. I went into the test not worrying about failing, but just a matter of how many questions until it shut off. I still had anxiety during the test, but it wasn't paralyzing.

You need someone to quiz you from an NCLEX question book. It is better for your confidence for you to hear that you are getting questions correct from someone else. Once you are getting 2/3 of them correct, then schedule your test and continue to review. Hopefully, you will come to realize that you have what it takes to pass the test and the anxiety will not sabotage your test taking ability.

Also, when you get ready to start the test, close your eyes and take 20-30 slow deep breaths until you feel a significant decrease in your anxiety. If need be repeat by closing your eyes and take 5-10 slow deep breaths every 10-20 questions when you feel the anxiety creep up.