I had a similar situation last semester with my Med Surg I class.. I needed to get a 76 on my final to pass.. seems low, but my classes averages were in the low 60s on ALL of the tests, I was better off than most! Our teacher wanted it that way. She is something else... BUT, I studied my butt off and came out with a 78 on the final. Yes, I was a straight A student before nursing school. And yes, many of the class failed and got set back a year. This instructor is just ridiculous. She thinks if she gives anything back she is cheating us of our "earned" grade. SOOOOO.. what I am saying is.. you can do it!!
This was the first B I have ever gotten, EVER. To tell you the truth, it opened my eyes to the real world. Nursing school is not about grades, it is about learning skills and critical thinking. Do not focus on your final grade in all courses, just try to pass.
If you haven't opened your textbook yet, it's too late now. Go back through your notes. Study from an NCLEX book. Anything but trying to cram reading will help at this point. Also, remember to breathe! Good luck! I am rooting for you!