Have an Answer?
I read your question and it was almost like looking back in time, because it is the exact question I asked every professional/family member/counselor/friend I knew when I was in your shoes. First, a little about myself. I am a 3rd year law student in Texas and, like you, I have always been driven by being of service to others. I was a Psychology major in College, even! So I get where you are coming from, completely.
It is so wonderful that you recognize your passion to help other people and that you want to make that passion your "Life's Work" as they say. In my opinion (and many others) - its the true key to happiness, fulfillment and success. Of course - as your question points out - there are a TON of different avenues through which you can help others professionally, and in a way that you feel truly makes an impact on their lives.
I think what you need to ask yourself is - "HOW do I want to help people?" and "What would I ENJOY helping others with?" Take Psychology, for instance - its a great pathway to helping others with their emotional, intellectual, and social problems..covering everything from dying marriages, to depression, medical disorders, phobias, anxiety, etc. Psychology is very medically oriented, as well. So if being a psychologist is how you would truly enjoy fulfilling your passion for helping others - then there you go!
On the flip side - a legal career is very different in that you are helping others in a more "objective" way as opposed to the "subjective" problems that people have like emotions, anxiety, etc. As a lawyer, instead of helping people deal with their demons on the inside - you will be preventing / defending their demons from outside occurrences, people, situations, etc.- meaning other individuals, businesses, etc. As opposed to (from a psychological perspective) helping people deal with what is stirring inside of them, even if the cause of their problem originated from an outside occurrence.
Of course - the two fields are incredibly intertwined, so trust me when I say that you are not the only one asking it. You can help people as an attorney with their subjective/inside problems as well - but its their OUTSIDE problems that are your opponent / ultimate goal. If the opponent others are facing is truly on the inside (depression, anxiety, etc) - and the ultimate goal for you / what would make you happy is to remedy those internal issues.. Then maybe Psychology is right for you.
Anyway, I hope you get a bit of insight from my answer and that it helps lead you down the right path. Ultimately, for me, it was answering and reflecting on those two questions above that led me to the legal profession - and I could not be happier. So I hope that you find those answers for yourself, and I admire your passion to serve others. The world needs more people like you!
All the best!