I am sorry to be that heart breaker, but at this point you need to consider some other career. As a F1 student myself I know its really hard from financial point of view and also from having to spend many more years of your life into something else. Having said that, 6 attempts is to much and personally as one of the hospital administrators who interviews nurses for job I will find it very hard to recommend you for any position that involves direct patient care and CE.