Take it from one who knows! I truly understand how you feel. I am now at my 3rd attempt, and don't know how to approach it. Wait until you get your results back to read the performance appraisal to see where you fell short. Many of the reviews are structured to teach you strategies of passing the nclex. If your problem is content, then these reviews won't help you.
Don't be so hard on yourself, it has happened to many, you right now probably feel like you are the only one, trust me, you're not! There were many before you and there will be many after you. Don't however look at the NCLEX as if it is just another test, because it is far from that. You have to train you mind to "read between the lines." Often times, the answer is not just sitting in front of you and you pick the right one. This test is structured differently. You have to know content, but you have to know test taking strategies as well.
Have you looked into any review options? I am currently enrolled in NCSBN, and just enrolled in Hurst Review online to refresh content and stratagies. I also earned good grades in nursing school, so failing the NCLEX twice was like a slap in the face!!
Try not to focus on the embarrassment and frustration of failing, just remember, many people have no idea of what you're faced with in taking NCLEX!! Good Luck!!