I have a few suggestions.
1. Do a search of this forum for efficient or effective study techniques and habits. the subject has been covered many many times so you will find some great info.
2. You say your problem is time management. Sounds to me like you need to treat your classes more like a job. This is something that helped me. What this means is from 8am-5pm you are at work. During this time you should be going to class, studying, perhaps some research or volunteering too on certain days. Of course it's important to take short breaks for studying to keep your mind fresh, but you should be able to get in at least 5 hours a day of studying. And this is baseline studying by the way. When you have an exam in the next few days, you will be fitting in more time at night.
With a 3.0 and only 2 years left you really need to start getting 4.0s. But I truely believe that anyone smart enough to get into a four year university can get 4.0s if they treat their education like a job.
3. On another note, you mentioned that your finals got away from you. The best way to combat this problem is doing your best to make your finals matter as little as possible. How do you do this? Crush the first midterms in all your classes. Treat the first few weeks of class like finals week. Starting with a 95% on the first midterm sets you up for success and minimizes stress for future exams. In addition, by pushing yourself early in the semester you are actually significantly reducing the amount of finals studying you will have to do because you will know the oldest material so well. It was often the case for me that I would go into the final only needing an 80% or so to keep my A. And the funny part was, I usually ended up doing quite well on the final without too much studying because I put the work in during the semester.
4. You asked about physics. The key is practice problems. Often times you have have weekly homework assignments of some kind. You should be getting 100% on these assignments. If you can't solve a HW problem, get help at TA office hours. If you master the homework you will likely master the exams because the hw problems are usually more complex than the exam problems. For me, physics and math was all about doing problems and seeking help when I was struggling with a particular problem set.
Lastly, if being a physician is your dream you are going to have to make sacrifices. You have dug yourself a bit of a hole with that 3.0, but it's not too deep. if you want this bad enough, it's within reach. Good luck!