i think for me some things in nursing school are harder than others. it depends on the class(subject being taught), the instructors, and what's going on in your life at the time. fundamentals(completely new subject matter), good instructors, great ci, not terribly hard; maternity-newborn-peds, totally new subject matter for me (no kids, never been pregnant) great instructors, wonderful ci, not too bad at all; med-surg ii, great instructors, difficult subject matter, ci with "personal issues, hard for me, and everyone in my clinical group.
just take each subject as it comes, don't stress too much, and keep one goal in front of you at a time. eyes on the prize as they say.