Hitoribocchi no Marumaru Seikatsu

is a Japanese manga series written and illustrated by Katsuwo. The manga was serialized in the Dengeki Daiouji magazine and published in Japan by ASCII Media Works under the Dengeki Comics NEXT imprint from November 2014.

Synopsis
Many of us know what it is like to transition to a new school with few to no friends in a new environment, going through the arduous process of getting to know people again. Bocchi Hitori knows this struggle all too well, having just graduated from elementary school and thrown into middle school. Unfortunately, she suffers from extreme social anxiety: she faints when overwhelmed, vomits when nervous, and draws up ridiculously convoluted plans to avoid social contact. It does not help that her only friend from elementary school, Kai Yawara, will not be attending the same middle school as Bocchi. However, wanting to help her, Kai severs ties with Bocchi and promises to reconcile with her when she befriends all of her classmates in her new middle school class.

Even though Bocchi has no faith in herself, she is determined to be friends with Kai again. Summoning all of her courage, Bocchi takes on the daunting challenge of making friends with her entire class, starting with the delinquent-looking girl sitting in front of her...

(Source: MAL Rewrite)

Anime
An anime adaptation of the manga, produced by Studio C2C, aired for 12 episodes between April 6, 2019 and June 22, 2019.