I am most definitely bipolar and have struggled with mental illness since I was a child. During both of my pregnancies I found that my mental illness calmed down quite a bit. With my first child I experienced severe post-partum depression, but there was really no safe med back then, so I just used other ways of coping (meditation, therapy, spiritual practice). Overall, pregnancy and breastfeeding were much easier and more joyful for me than my life usually is. I would not let your mental illness get in the way of having children - there are so many treatment options nowadays.