She also said that I might want to consider using
formula for one night feeding, even though otherwise I'll be exclusively
breastfeeding, because PPD is linked to sleep deprivation.

reporting back from my appointment, when I asked about what I can do to help
things, the first thing the psychiatrist said was sleep, but he did not
suggest missing feeds, or not breastfeeding at all, but that if I start to
not be able to get to sleep easily as happened last time before I slid into
depression that there are things I could take that should help me get back
to sleep easily but not be a problem with waking up, if this is the case,
this could be really helpful for me, as from when ds was about 4 weeks old,
I would take so long to fall back asleep after each waking that I sometimes
only got half and hours sleep between feeds