Check out Stanford univ breast feeding site. There is a link to the breastfeding/safe meds list.
I had bad ppd w first, and started meds immediately after birth of second. I feel so much better this time. I was able to take a med which is safe for BF'ing. But if the choice was non-crazy mama (on meds) or ff, I would ff for sure. Your baby needs a happy mama more than anything else.