心比大姨妈来的还痛
[xīn bĭ dà yí mā lái de hái tòng]
It literally means 'My heart feels more hurt than getting a menstrual cramp', using exaggeration to indicate intense emotional pain. In Mandarin, dysmenorrhea or painful periods colloquially called “big aunt” (or '大姨妈' in Chinese) is often used in metaphors to express extreme situations.