LO is about 4 weeks old and we breastfeed except for one nighttime formula session. I've never noticed the letdown before; the milk just started flowing and that was that.

The last few days though, I've noticed when she starts feeding on one side, the other side gets these stabbing sort of pains in my nipple. (it hurts for a bit on the side she's feeding, but not as bad) They go away after a little bit, but it's just nothing I've experienced before. I haven't seen any sign of thrush, so I was wondering if anyone else went from a painless letdown to a painful one, or if there is something I should be doing to minimize the pain!