Don't worry about anyone else. What they're doing doesn't matter. For all you know, the guy studying for 900 hours in the library for that test is either using AIM and iTunes for 98% of that time. Some really smart people really do study a lot, but there are plenty of people who waste a ton of time. I certainly had to take my share of study breaks in the first two years, or else I'd go nuts. You have to find a balance that works for you, and only you.
I skipped most lectures, and I read and read and read the lecture notes. I used some textbooks and some review books, but I mostly used our lecture notes. I didn't listen to recorded lectures, and some of my classmates were stunned. At first, I was scared that I was missing out on something important, but after listening to a few lectures, I realized that it didn't help me out. It helped other people, but not me.
Now, if your performance is terrible, you should change your strategy, but once you find something that works for you, do it. If it's more efficient and relaxing than someone else's study schedule, you might have more free time and less paranoia.