My Socialite Roommate Bound Me to a Swapping System

On the day we started school, my roommate gave me a crystal bracelet as a welcome gift. I hurriedly put it on her mother's wrist instead. In my previous life, my roommate wanted to be a social butterfly and was determined to date during college. No matter how wild she got, she never got pregnant. I was the one who suffered through pregnancy. The whole school laughed at me. After I miscarried, I died on the operating table from blood loss. Only after I died did I learn that the crystal bracelet my roommate had given me bound us together through an exchange System. When I opened my eyes again, I was back on the day we started school.