I wouldn't quit, I would go to the library, bookstore and find as many exam prep courses as you can find and start doing questions. Schedule your exam for as soon as you can take it again then study your butt off. It may help to go to a Sylvan Learning Center or similar tutoring center to see if you have a problem with test anxiety.
They have programs that can help.
Wish you luck!
Andrew Lopez, RN
http://www.4nursing.com