Let me give you my insight, since I was in the same situation as you.
In high school, I was one of the laziest people you would ever meet. I would procrastinate on a whole semester's worth of homework and do it all the night before the last day and turn it in (rolling turn in). I would simultaneously start reading, outlining, and "studying" for an exam the block before the actual test. I would basically play games, watch TV, and do nothing academic when I got home until 1 or 2 am.
Basically, I had atrocious work ethic. I didn't bomb school (decent GPA, 2170 SAT, 33 ACT), but that was only because high school was easy. But, it's completely different in college.
When I got to college, the whole environment was different. I had much more free time and had much more time to chill with friends and basically was FREE from the mindless institution known as high school. I found the reason for my laziness. It was because I was absolutely sick of the boring "wake up, go to school for 6-8 hours, come home, do whatever, go to sleep, repeat the next day" routine.
Sorry for this long post, but what is my main point? College is MUCH more different than high school. You don't burn out as easily if you can manage your time. You have so much free time and the workload is very manageable, if you break it up. I'm basically all caught up with all my work and, by the looks of it, I'll be pulling straight A's at the end of the semester. In high school, I put everything off til the end because the only time I had to do hw was afterschool. Now, I'm free to do whenever.
Now, I can do it in the morning, in between classes, after I come back from the movies, etc. It's very liberating and I'm actually motivated to do the work. You can even skip lecture and do it. Nobody cares.
For you, this might be the case too. Many "2.0 GPA high school slackers" rise up to the challenge in the new college environment because it's so DIFFERENT. No one's here to hand hold you. You're free to do whatever. Some people actually thrive in this sort of environment. I was one of those people. Your work ethic may actually turn 180 degrees because college is so different from high school.
Now, I'm not saying that there's a 100% guarantee that you'll instantly change. But, you'll be surprised how much will change once you're in college. Let that be some encouragement for you. You're spending MONEY to study here. You're an adult now. Act like one.