As Damon also answered, the most important part of picking a career is finding something that you care about and that you will enjoy doing day to day. Learning more about yourself is always a great starting point when exploring potential options.
It is great that you want to help people. I would ask you to start with how you could start helping people today. What talent or skill do you already have? Are you artist? Are you a great listener? You should begin your journey to find a job by thinking about what you are good at or what you like to do. Playing to your strengths and passions will help you through the hard times. College is not easy, even when you know exactly what you want to do. Having that passion will help you be patient or work harder when it feels difficult to do so. If you are not certain about what your skills are, ask people around you. They can see you more clearly than you can see yourself. I would also recommend talking with people around you who have jobs that sound interesting to you. See if you can spend a day with that person to see if you would really like it. Don't be afraid to look at various types of jobs, especially if you have no idea what you want. Another way to get new experiences is through volunteering. When you volunteer, ask to take on the job that you don't really understand so you can get experience.
Good luck on your career search.
What motivates you?
What brings you that sense of fulfillment?
Think about what it is that you can picture yourself doing everyday that would make you happy.
This is how you begin the find your most effective way of helping others.
I think there are various career paths that you can take to help people. First option can be a medical/health care path. Doctors and nurses are the main occupations that help people gain their health back, but there are also health trainers, psychology counselors, pharmacists, etc.
Educator can be another choice to help people out. You can be a teacher at school and also go aboard to teach English in foreign countries. This field also includes career coaches and professors.
Lastly, humanitarian jobs can help people who are in basic need. It is usually related to government agencies that are specialized in planning infrastructures for undeveloped countries or helping people in emergencies or natural disasters.
If you still have not found what you would like to do among these options, I would like you to think how you want to help people. It is important that your career path is something you also might enjoy doing.