100 mg of Lamictal is still a pretty low dose, so definitely mention your concerns to your pdoc. Maybe you also have anxiety going on -- she or he is the one to help you figure that out. I think all of us parents worry about what would happen if we're gone, but it sounds like your thoughts are making you miserable.
It's funny how many of us don't want to have to tell our doctors our symptoms, yet we show up for appointments and pay for their time....