1. Everything is so competitive! You even have to apply to get into clubs at my school - and yes, I was rejected from a couple. I also approached 8-10 profs just to get one volunteer research position.
2. The material. It's not hard; there's just a lot of it.
3. Anatomy would've helped. :/
for the club thing...yes or no.
Yes, you do have to apply. But unless you are only aiming for the president or vice president of a club, then there are a lots of openings for you to choose. There are so many clubs in school, and there are so many different so called "leadership" positions such as secretary, treasurer, event organizer/planner / public relationship, so-and-so chairs (there are so many different chair positions available).
The problem with that is, mostly if you want to , you can get a "leadership" position. But then, there are the competition part---how do you set yourself apart from everyone else with the similar title? Everyone has a leadership title, everyone also work 1 or 2 job, everyone also have extra curriculum in volunteer, going to conference, "networking", doing poster presentation, etc. Everyone just look very similar in CV.
You try to set yourself apart, but everyone else is doing the same. I would imagine most students have very similar CV. Then at time to apply for job, I think it is more like who knows you and likes you can give you the job, not much about qualification. This would be even more true the longer in the future, when more student graduate, and less job available.