D.W.
I've always been a working mom. I knew before I had kids that both being a mom and having a career would be important to me, and it's not easy to balance both.
My advice: follow your heart. Find something that allows you to have that personal fulfillment. Only you will be able to know what that is with the support of your family.
You obviously pursued a graduate degree because you're a smart woman who wanted to do something with it. After all these years, you may find that your passions have changed now that you have a family and have seen the world through different eyes.
Don't be discouraged, though, if it's tough to find something if you decide to do that route - the economy stinks right now (as if we've all been living in a cave). But, anything is possible. I hope you find the fulfillment you're seeking outside of what life is already blessing you with.
Good luck!