Psychiatric Nurse, Psychiatrist or Psychologist?

I'm currently a freshman in college with a nursing major. I've been torn between the career I want to eventually pursue and I'm looking for some advice. Ultimately out of a career I want to be able to help people, be an outlet for them and help them through their problems, but I also love the biological and scientific aspect and would like to be able to help them medically. I want to take a holistic approach. I don't mind how long I'm in school for, and regardless of whether I become a nurse or doctor or psychologist, I would like to have my own private practice. I was thinking to either double major in nursing and behavioral neuroscience, stay with nursing and minor in psych, or switch to behavioral neuroscience, pursue med school and if that's not the route I decide to take, then I'll enter the accelerated nursing program. My issue with letting go of nursing is the job security and being able to get my degree, then work as I pursue other things, possibly med school. I know I'm only one year into college and people change their majors all the time, but I'd rather figure this out now and not waste $50,000 a year...help!