u/Inevitable-Cat-9540

Hi! Mom of 3u3, breastfed 2 & 1yo (tandem until I got pregnant the third time). Weaned them then. New baby is here and I'm struggling to get my supply up and feed her, but most of all struggling because I'm only getting the letdown reflex when my toddlers cuddle me, not when nursing. Why is this happening? Can I fix it?