Is it worth it??

In recent days I have added a new role to the list of many that I already have.  I will call this one: Guilt Ridden Parent.  As a result of graduate school, the schedule of my family has had to change quite a bit.  My husband works 6pm-6am, so in order to participate in live class sessions and also to complete homework, we have had to hire a nanny to come to our home to help care for our two kids.
This has had a direct impact on my 3 year old.  In the last month she has displayed an incredible amount of aggression towards the other kids in her preschool class.  Today we have a school meeting in which a mental health professional will be present to discuss a "treatment plan" for my daughter.  Did I mention that she is three??  The grades of my 11 year old have begun to slip as a result of my decreased time spent doing school work with him.
I made the decision to go back to school for my family.  However, is the resulting damage worth it?  The guilt I feel is overwhelming.  Is this a phase or am I helping to create long term damage?
As I am weighing this out, I am also thinking about the $40,000 that graduate school is going to cost coupled with the dismal at best communication with instructors.  I am paying just as much as on campus students, but they get a few hours a week of time with instructors.  I can hardly get an email.  It is only week 5 of 182 weeks. 
I am going to school to enhance my lifelong desire to have a positive impact on the lives of children yet my own children are being negatively impacted.  The irony isn't lost on me.