AF returning and supply dip

shocked77

LO started sleeping through the night in April and like clock work i got my first period beginning of May.  I noticed a pretty significant supply dip about 3 days before AF started and then it slowly picked back up.

I read in my Ina May BF book that its common for your period to cause your supply to dip.  My question is will it dip each time a cycle or just the first time.

I generally can pump exactly enough at work for what my son drinks at daycare and when my supply dipped in April I had to dig into the stash.  So scary when you can't make enough!  I am so committed to nursing and will be devastated if I have to go to supplementing with formula.  I don't have a huge freezer stash and LO is only 7 months old so I don't know how long i'll be able to dip into it for supplements.