High School to college can be a rough transition. You really need to be able to use your time efficiently. If you think you worked your butt off in high school, you will be in for a rude awakening once you reach college (if you want to do well), and probably go into shock once you see the workload of med students.
Having said that, you will eventually become adjusted to just "going to the lib to study every day" instead of going out/hanging with friends. Personally, finding a close group of friends in each class helps a lot, as I usually "hang out with friends" while studying.
Some key tips that I feel definitely helped me:
1) podcast/listen to recording of lectures
2) take your own notes (whether it be from recordings, or powerpoint slides - you remember more material this way)
3) try to formulate your own questions from the material; this will help you interpret the material better and after a while you will be able to "read" your teacher and what type of questions he/she likes to ask
4) after a thorough review of your notes, quiz your friends and have them quiz you on the material
for example, for a bio test, I might have to go over about 300-400 slides. If they are self-explanatory, I usually condense these slides into 30-40 pages of notes (takes about 1-2 days). I then review my notes for a day or so, then quiz my friends. By this point I'm usually very prepared. Keep in mind, that if you want to do well, you can not procrastinate (I start studying for an exam about a week before).
Rule of thumb is that in undergrad, you will work as hard in one semester as you probably have in 2-3 years of high school, and in med school, you will work as hard in one semester as you have in 2-3 years of undergrad. Like I said, this might be somewhat of a shock to most people, but just get your bigboy pants on and you'll be fine/adjust.