Unsane (2018)

Sawyer Valentini is a data-analyst driven from her home in Pennsylvania to Boston by a stalker. Determined to rebuild her life while keeping people at bay, contact with those outside of the office becomes relegated to only calls to her mother and no-string random hookups. Unwillingly, she is committed to the Highland Creek Behavioral Center, for what is initially meant to be a 24-hour stay. Soon, the staff is questioning her sanity and Sawyer finds herself wondering if George, a nurse assigned to her ward, is actually David, the stalker that sent her fleeing.