Lost your period? You might just need to eat more. A lot more. Losing your period to undereating is called hypothalamic amenorrhea and is common, especially in women under thirty.
Hypothalamic amenorrhea is sometimes misdiagnosed as polycystic ovary syndrome (PCOS) because both hypothalamic amenorrhea and PCOS can have “polycystic ovaries” on a pelvic ultrasound exam.