Why do I feel flu-like during my period?

Feeling “flu-like” during your period—achy, wiped out, foggy, sometimes even slightly feverish—often reflects a surge of inflammation and immune signaling that can happen as the uterine lining sheds. Prostaglandins and other inflammatory mediators can drive body aches, chills, headache, nausea, and bowel changes, and the overall physiologic stress of bleeding plus pain can leave you feeling like you’re coming down with something.

When these flu-like symptoms are intense, worsening over time, or paired with significant pelvic pain, bowel/bladder symptoms, heavy bleeding, or deep pain with sex, we start thinking beyond a “normal period.” Conditions like endometriosis and adenomyosis can amplify inflammatory activity and pain—sometimes far out of proportion to what routine exams or basic imaging show—and fatigue can also be compounded by heavy bleeding and iron deficiency. If this pattern keeps showing up month after month, our team can help you map your symptom timing, evaluate likely drivers, and discuss options that range from targeted medical management to definitive diagnosis and treatment with minimally invasive excision when appropriate.