During the trailer of the film and early in the film, Sam is about to have a class on Sisyphus. Those familiar with the myth will know this refers to Sisyphus, who was forced by the god to push a massive boulder up a hill endlessly for eternity. Coinciding well with Sam's story, Sam struggles with the task of the futility of being unable to change her fate until she comes to an epiphany, similar to Sisyphus.
One of many movies where the protagonist must relive the same day over again in a loop. Other examples include: Groundhog Day, 12:01, Edge of Tomorrow, I Do I Do I Do, 12 Dates of Christmas, Pete's Christmas, Source Code, Happy Death Day (2017), Christmas Everyday and 2:22 (2017).
Halston Sage and Logan Miller previously worked together in Scouts Guide to the Zombie Apocalypse (2015) where Sage played the older sister to Miller. Here they play students in the same year at high school.
If you look at her phone at the beginning of each loop her phone reads February 12th. But after she leaves the party with her friends if you look at her phone when she holds it up, it reads Saturday February 13th just before the loop ends and repeats itself.
The trivia item below may give away important plot points.
An episode of the X Files (S6 Ep14) also dealt with a female reliving the same day and being unable to change the outcome no matter what she did. It was only until she was killed, that the day stopped looping. Interestingly, Nicholas Lea, who plays the father, had a recurring role on the X Files.