Don't know what to be when I grow up

I need help, like professional help, I'm afraid!  I find myself completely conflicted about school and career paths.  This is a total "first world problem." The kind of problem that women in developing countries are never faced with because they are oppressed, poor, and although very capable and bright, denied opportunities for education and advancement.  I give that disclaimer because I want it known that I truly "get it" that I'm blessed to have such choices about my future and have seen with my own eyes, in several other countries, the realities women and mothers face.  Could God please just write on the wall what I should do about school?  I jumped in to grad school in January with the plan of becoming a Family Nurse Practitioner.  All this stemmed from a medical mission trip to Haiti in January of 2010.  Oh, combine that experience with 17 years of bedside acute care nursing(working 12 hours shifts, holidays, and weekends) with people getting more and more overweight and thus straining my back and joints! Pretty much, I can't do what I'm doing much longer.  N.P. sounded like the perfect spot for me.  I can serve medically underprivileged, go on international medical mission trips, use my experience and be challenged, all while making a good paycheck. So what's the conflict??
I...don't...like...school
I...don't...want...to...work...full-time...ever

Admittedly, I've only taken 1 class and it was dreadful(as all entry level graduate classes are).  My class that begins June 4th is Research.  RESEARCH...Gag me please.  I feel like I was a terrible mother the past 4 months because I was stressed and tired, trying to read and write papers, and also be mom to 4 children.  I say I want to become a Family Nurse Practitioner so I can be more useful for missions.  But, my family is my first ministry priority.  See the dilemma?   If I sail through school and become a successful N. P. but missed my kids games, recitals, and shooting baskets in the driveway and stressed out my husband because he has to work and take up the slack at home for me to study...I've sacrificed all that is important! Carter is about to enter is Senior year of high school.  Its almost over....my role of parenting him is nearly over. And, it is not entirely impossible that we won't adopt again..unlikely yes.
On the flip side, I know I can do it and I don't want to be a drop-out!  I also recognize that I have a character flaw--I always want to quit what I start.  I remember having an argument with my mother when I was 19 because I'd said I wanted to do something, but a few hours before the event, I said I wanted to quit. She, rightfully so, pointed out that I always want to quit after I begin something(piano, gymnastics, etc....)

On more thing, my nursing career isn't what fires me up! Oh sure, I love my job and get great satisfaction from taking care of patients.  But, you know what makes my insides burn and ignites fire in my heart??  Precious children with no family.  Orphan care and adoption....That is my true passion. Homeless Children What can I do for that and use my nursing experience??