I had a similar experience when I did my NCLEX in March. Over half of my NCLEX contained SATA questions and I only felt confident in answering 3 or 4 of them. Right from the start, I found the questions difficult - I remember being only 6 questions deep and thinking, "WTF IS HAPPENING?!" Some of the questions were REALLY SPECIFIC about certain diseases and medications, some of which I haven't even heard about so I had no choice but to guess the answers. I was devasted when my exam stopped at 75 questions as I was sure I was going to get more than the minimum based on how poorly I felt that I answered some of questions. Fortunately I passed but it was a rough couple of days before finding out my results. I also used UWorld to study (among other resources like a hardcopy of Saunders) and would consistently score below 80% in most of the question blocks I created. I felt that UWorld prepared me for the layout/style of the NCLEX and maybe SOME content, but I found the NCLEX to be way more difficult than UWorld.