What was this manga?

FL killed her dad because her other “dad,” who has red hair, told her to do it. But it turns out the person she killed was her real dad, and the red-haired dude liked her mom, so he wanted to kill everything that was in the way.
Somehow, she travels back to the past, now knowing the red-haired dude isn’t her dad and is trying to make her kill her real dad. She also meets someone in the middle of the night — a young boy — and she gives him a message. Later, he tells her real parents when he comes to congratulate them because the mom was pregnant. He sees the mom's hair and remembers what FL said, then tells the mom about it. I believe her message was something like “I know what going on and who I am but for now wait for me” or something like that