Angel,
The personal statement is a great time to explain in detail why you want to go into medicine. It sounds like you have some ideas/reasons for wanting to pursue a career as a physician. Take those ideas, and spend the next 4 years exploring them.
Let me give an example... Do you enjoy working with people? Spend some time volunteering in a hospital, or a nursing home, or a daycare... Interact with people and enjoy yourself. When you get to the personal statement you can say, I enjoy intereacting with people and my time volunteering at the hospital really opened my eyes to how much I'd like to work with people in medicine.
Is your interest that of your love of science? Get involved with some biomedical research at school. Explore the ideas... Then you have "evidence" that you really do enjoy science and research.
I could go on forever. I think it is very important to present yourself as a well rounded applicant. If you have reasons for wanting to be a doctor, go explore facets of them and enjoy them. Not only will it better prepare you for medical school, but you will enjoy yourself in the process.