I also have to agree that Kaplan ( I used this for Q's and Saunders Comprehensive to review material ) was more challenging than the NCLEX. Definitely do Qtrainers 6 and 7 because they contain more challenging questions and be prepared to sit for the whole exam- I believe they are both around 250Qs. You can walk into the nclex and get as many at 265Q, you must be mentally and physically prepared to sit for the whole thing.
Most importantly, do not give up! You spent all of this time trying to prepare for this exam and its certainly not worth giving up on D-day! Sample test 4 was brutal, but keep in mind the NCLEX is filled with alt type questions so you must be comfortable with those- don't be afraid of them, if you get them wrong thats okay!!! Read the rationales so that when the test comes you will be well prepared. Also focus on your weak areas- peds, maternity, pharm because you must pass each section in order to pass the nclex- although i didn't get many questions on any of those sections. Wishing you the best of luck!