Another momma on one of my Fb group is nursing on it. She called infant risk 1(806)352-2519 and they said it would be safe
but you need to talk to your psych and pediatrician. I would also see if there may be an alternative med that works for you that is a lower risk. But honestly I would be more worried about keeping my mind in tact after baby then breastfeeding (I may get tons of hisses at that) but as a person who suffers mental illness, is a psychology major and also suffered PPD, Your mind is more important for you and your baby so I would do evaluations and get all doctors input. i would even pick a pedi and talk to them before the baby is born. Sometimes you can even get your psych and pedi to meet up to decide on the best treatment for both.
I wish you tons of luck and

its a difficult issue to deal with.