Breastfeeding and menstruation

Does anyone here have the same supply issue that I have when your cycle kicks in, starting from ovulation time?? Last month my supply was so low my son lost weight so much that he dropped from 57 % to 23%. I don’t know what to do. Any tips? I’ve been taking ca/mg supplement (500mg per day). Also breastfeeding supplement with fenugreek in it).

This month I’m starting to feel low again, this can be confirmed by the lack of wet diaper and dry poop. I’m so frustrated and i dont know what to do. My son still doesn’t eat solid much either (he’s almost 11 mo). And under 1 yo breastmilk still is supposed to be the main source of nutrients.

I don’t pump because my son just want to direct breastfeed.

Please help!