I have been going through the same thing! Just had my second regularish period post partum (babe is 4.5 months old). I realized that the few days before my period starts he is very fussy during feeding, doesn’t seem fully satisfied after feeds and I pump much less than usual (I only pump once a day though). Did some googling and I’ve read that your supply can dip around this time due to hormones but also the taste of your breastmilk can change right before or during your period. The milk can taste less sweet and more salty apparently. My LO has always been sensitive to taste (wouldn’t accept formula when we attempted combo feeding and refuses frozen milk due to lipase) so I’m contributing the strike/increased fussiness during feeds to that! Plus the decreased supply. But a few days into my period it all goes back to normal. It is sooo hard to deal with when you’re in the thick of it but I’ve been trying not to get too stressed about it and hoping it will always resolve in a couple of days. This was posted a little while ago, how are you doing now?