Thankfully, my epilepsy didn't get really bad until a few weeks ago and I was able to have 4 children without it being a concern. However, I can say that if it had been, I still would have tried to have at least one.
For some women, pregnancy makes the seizures more frequent and more severe, but in others it does the opposite. Those hormones are a tricky thing!
You just have to trust God and His plan. He gave you this child and if you can trust Him to keep you both safe, you'll be fine. It won't be easy, but few things in life really are.
As for breastfeeding, I wouldn't personally feel comfortable being off my meds for that long, but you do have some options if you aren't able to. There are breast milk "banks" where lactating women "deposit" milk and people can purchase it. Additionally, raw goats milk (not super easy to find, but I have a great source if you want it) combined with a folic acid and vitamin supplement, is a great substitute for breast milk.
Keep us posted on your decision and what the doc says!