introvert conundrum

I think I'm starting to realize why I'm having such a problem with my future plans.  I'm an introvert.  I'm a shy introvert.  I don't ever feel comfortable talking to people who I don't really know.  I never know what to say and I feel like I always say the wrong things.  The problem is that all of the careers I'm interested in involve working with strangers.  So I'm feeling super conflicted.  It's like I'm struggling against myself.  I know that I would be good at nursing or social work or something like that.  But the thought of having to talk to people all day long and advocate for people and talk to strangers all the time freaks me out.  But I don't know what I would do instead.
I don't particularly want to work at a cubicle in a giant office doing paperwork or whatever.  I want to do something hands-on where I can see that I'm making a difference.  So it seems as though I would be well-suited to working with people as a nurse or a social worker or something like that.  But I'm just afraid that I'm not extroverted enough.  I'm worried that I will be really bad at it until I get comfortable.  And I don't know how long it will take for me to feel comfortable.
Sometimes I think that life would be a whole lot easier if I was an extrovert.  I would have lots of friends and I would feel comfortable talking to all kinds of people.  But then of course I wouldn't be me.  And I know that I'm pretty wonderful (or so my mother tells me).  I just wish that I was a me who felt totally comfortable talking to strangers.