What causes nausea one week before your period?

Possibly PMS: Premenstrual syndrome (pms) symptoms can include pelvic/ abdominal cramping, nausea, bloating, weight gain, moodiness, irritability, pain ; swelling of breasts, feeling tired, insomnia, headaches, ^ acne, food cravings, ^ appetite, swelling of hands ; feet, dizziness, thinking less clearly, urinary sxs ; exacerbation of chronic conditions.