Risu ni Natte Shimatta Kon'yakusha ga, Kegirai Shiteita Hazu no Watashi ni Tasuke o Motomete Kimashita.

Count Amelia, daughter of the Countess, has been abused by her family and disliked by her fiancé, Cedric, who sees her as unsociable. Amelia lives a life supported by her beloved job as a pharmacist, but one day, someone comes to visit.. Cedric, who has been poisoned by someone and turned into a squirrel!? "Please let me stay in this room," Amelia pleads, and so begins her strange cohabitation with her fluffy fiancé (the squirrel)! (Source: Kadokawa, translated)