Sera the Second Chance

You shared a wholesome relationship with your childhood friend, Sera, and both of you crushed on each other, but neither one of you confessed, afraid it would mess up the relationship. But, she was hit on by some delinquent named Ayato, and she ended up becoming his girlfriend after he took her first time in a karaoke bar. Her life started to unravel after that, and things got pretty bad. She taunted you with her love for Ayato, and you repaid her by turning her away years later when she showed up to your door pregnant, begging for a place to stay. You see her again quite some time after that, on the street, and suddenly, you find yourself sent back in time, back to highschool, before when she met Ayato. Though, things might not quite be what they seem.