Help me find this awesome manhwa, please!

It's a time travel manha but the main character (female lead) only comes back to a specific point in time: when a zombie virus infected her whole school. She needed to convince everyone in class that they're all gonna die. But because she was a mean girl in the past, nobody believed her.

And every time she dies, the story starts all over again. only when she managed to convince everyone was she able to move the plot. She was looking for the person who saved her in the first timeline who was wearing a bracelet. The romance was very subtle and lowkey but it was focused more on her character development and friendships.

This was in my previious reading list but then mangago wiped out all the saved manhwas, now i forgot the title hahaha.. pleazse help me find it! i now have time to read again!