Plain ol' ordinary...
I'm taking Social Work in College right now and know exactly how you feel with the whole "purpose in life" thing. I'm one of those people who can't wake up in the morning without having a reason to get up, if that makes sense at all. I can't picture my life not working towards a profession where I'm helping people maintain their lives and get better.
If this is your passion, then, by all means, go for it. I know that's not a very good response, but I guess I just wanted to wish you good luck with letting your family know your desire and all that.