Help! How Did I End Up in Another Dimension Again?

[Infinite flow, no romance, heroine stands alone, a little angst in her coming-of-age journey, clear goals and a decisive, fearless personality] A promising employee is swept into an alternate space and is about to be offered up as a sacrifice. To save herself, she begins deliberately entering these spaces in search of a chance to survive. In one alternate space after another, she discovers that everyone around her has another identity, and she also uncovers what makes her different, along with an entirely new set of rules governing the world...