I have two little ones, as well. Until I had my second baby around Thanksgiving, I just sort of dealt with my anxiety. However, I just couldn't face going home with a newborn without some help, so I left the hospital on Prozac. Like others have said, different meds work differently for everyone. This is the first time I have tried anything for my anxiety, and I'm lucky that the Prozac has worked, and it's been life-changing.
However, I am also seeing a therapist, which has been good for me too. I know it's really hard to find the time - I stay home with my children and we don't have any daytime babysitters, so I schedule my appointments while my older child is at preschool and I bring the baby with me. But it really has helped sort me out and I'm able to better recognize my triggers and try to deal with situations before they get the better of me. I'm stressed out that my son is out of preschool for the summer so my appointments are put on hold until the fall.
Anyway, sometimes anxiety and/or depression can manifest as irritability and rage. It doesn't make you a mean mommy, it just means that a different med might help you more than the Lexapro did.