the nclex is designed so that you only get 50% of the questions correct. it is the difficulty of the questions you get right, rather than the absolute number, that determines if you pass or fail.
since 15 questions are "experimental" and don't count in your score, you could quite possibly get less than half of the questions correct,
and still pass.
since the passing standard in most nursing programs
is somewhere around 75 or 80%, it tends to feel
as though you failed the nclex, because you arn't used to getting such a high proportion of your questions wrong on a test (and passing).
i, too, got 75 questions on the nclex, and i was certain i had failed. there were just too many questions i wasn't sure about. i was wrong; i passed. so try to relax a little. true, there isn't any guarantee that you passed, but it is totally normal to feel as though you didn't pass.
(sometimes i wonder if the nclex authors have stock in the pharm company that makes xanax.)