Weaning from breastfeeding is one of the most significant hormonal transitions a woman will experience in the postpartum period — and one of the least clinically supported. This post explores why the 3–6 month postpartum window, when most American mothers are weaning, is a period of compounding vulnerability: shifting reproductive hormones, the return of estrogen cycling and menstruation, postpartum thyroiditis (which affects 5–10% of postpartum women and often goes undetected), cumulative sleep deprivation, and the withdrawal of oxytocin and prolactin can converge into a perfect storm of mood disruption that is often more destabilizing than the early postpartum period itself. While breastfeeding is consistently associated with lower rates of postpartum depression, the direction of that relationship is complex — and the medical literature on post-weaning psychiatric symptoms remains startlingly thin, with only thirteen documented syndromes across six published case reports, even as thousands of women describe the same experience in online communities. Drawing from both personal experience and clinical practice, this post examines the neuroendocrine landscape of lactation and weaning, the emotional weight of ending a breastfeeding relationship, and what evidence-based treatment actually looks like — including interpersonal and cognitive behavioral therapy, SSRIs and other medications, psychosocial breastfeeding support, and the kind of compassionate, unhurried care this transition deserves. If you are experiencing mood changes, insomnia, or anxiety during or after weaning, this post is for you.