I had a very rough transition into college because I literally did not pick up a book throughout my entire high school career. I'd just show up, take the tests/quizzes, go home and pass out before dinner and more sleep. Transitioning to college was rough because A) not only did I have to study to actually do well, but B) I now had infinite freedom. I'd much rather stay out late everyday than study for my exam later on in the week. This resulted in a terrible GPA, but I reached a point where I realized that I needed to step up my game. This is the point where you're at now.
I think at this point I had a 2.68 GPA, so I knew I had to pull a straight 4.0 for the rest of my college career if I wanted a shot at dental school. The key for me (and you might find a better alternative for yourself) was to basically tank my social life for about a month. The first month of my Junior semester I didn't go out at all and focused only on studying. That helped set up the frame work. I learned how I studied best and started setting up a study schedule. After the first month I went out sparingly, but I think I was taking 18 credits that semester myself (with two two-a-week labs... ugh) so I didn't do anything too crazy.
The semester after that, I had a good idea on how I studied best so I mixed in some DAT studying which also kept me pretty busy. After the DAT was over though, I realized that I could cut back significantly on the amount of time I studied because I already knew the most effective way to do it. Finishing up my last semester of undergrad now, I don't study nearly as much as I did that first terrible semester, but I still get the same grades.
Moral of the long-winded Story: The key is to learn how you study. Take some time and try to focus SOLELY on studying. It'll suck, but you'll be thankful you did when you find out the best way to utilize your time.
Good luck, and know you can totally do it!