I had this with my last DS last year and just started having it again with my 3 week old DD.
Just before/during or after for a few minutes I get this overwhelming sense of sadness and anxiety. Almost like my world is ending and I have nothing to look forward to. But because I know it's because of the Let down I'm not that phased by it anymore.
I just did some searching on DR google and found out it has a name! Dysphoric milk ejection reflex!
Does any one else have this?